Entrance i

Entrance i

1590405742

NCERT Solutions for Class 11 Science All subjects|Entrancei

You will learn many new ideas like electricity in physics class 11. The current flow in metals is based on free electrons. In the absence of an electromagnetic field applied to the outside (using a battery), the free electrons move randomly through the metal from one point to another and cause a zero net current .

When connected to a battery, free electrons accelerate due to the electric field generated by the battery and gain speed and energy. However, the passage is not smooth and the electrons collide with the crosslinked ions whose final gain (energy) is the ion. Since we know that body temperature is related to the vibrational energy of these ions, these collisions cause the temperature of the metal to increase. The energy loss of the colliding electrons and their acceleration by the electric field ultimately causes the electrons to drift in a certain direction. (Although the actual movement of the electrons is irregular, the general effect is that the electrons drift.) In addition to this mechanics, the most important part of class 11 physics is where you learn that movement means changing position over time. When a body is at rest, its position does not change over time. But how to describe the position of a body? To do this, we must describe it in relation to another body as a reference.

Rest and movement are therefore relative. A man seated in a car traveling on the highway at 55 km / h is resting relative to a traveling companion while moving relative to a person standing on the highway.

To describe rest and movement, we select a frame of reference, and then describe rest or movement relative to that frame of reference.

There are two types of movements: transnational and rotational.

If a body moves in such a way that it always remains parallel to it throughout the movement, it is translated. When a body moves so that each point on the body maintains a constant distance from a fixed axis in space, the movement is a rotation.

Chapters of Physics class 11 Notes

Chapter 12 Chapter Exam Notes for Class 12 Physics
Chapter 1 - Charges and electric fields
Chapter 2 - Electrostatic potential and capacity
Chapter 3 - Electricity
Chapter 4 - Mobile charge and magnetism
Chapter 5 - Magnetism and matter
Chapter 6 - Electromagnetic induction
Chapter 7 - AC
Chapter 8 - Electromagnetic waves
Chapter 9 - Radiation optics and optical instruments.
Chapter 10 - Wave optics
Chapter 11 - Dual nature of radiation and matter.
Class 12 electricity and electric fields.
Chapter 13 - Hearts
Chapter 14 - Semiconductor electronics: material, components and simple circuits.
Chapter 15 - Communication systems

Why Entrancei for Physics Class 11 Notes

The entry academic team is made up of a team of very experienced teachers who have prepared a special academic resource for physics class 11. We have prepared several sections for class 11 physics for students preparing for JEE and preparing for the CBSE board exam. Our team knows the needs for class 11 physical resources and how to use them. You can get detailed physical notes for class 11 chapter by chapter with additional resolved and unresolved examples. Each chapter of class 11 physics notes consists of one to five exercises with objective questions that improve the learning of the chapters. Ncert solutions for class 11 will help you pass the exam prepared by our academic team. On the same page, you will find an online questionnaire chapter by page for physics in class 11. The model of the online questionnaire is similar to that of exam management. In addition to these resources, you can read important questions for class 11 physics and various segments for class 11 physics formulas. In addition to the resource mentioned above for class 11 physics, you can download documents from the previous year, examples of documents for class 11 physics, key chemical formulas and a list of name reactions in organic chemistry. In the section on chemistry questions, you will find many class 11 physics questions that have been answered using examples.
Source Url: https://bit.ly/2LXEt9O

#physics class 11 notes #ncert solutions for class 11

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NCERT Solutions for Class 11 Science All subjects|Entrancei
Kaia Schmitt

Kaia Schmitt

1659817260

SDK for Connecting to AWS IoT From A Device using Embedded C

AWS IoT Device SDK for Embedded C

Overview

The AWS IoT Device SDK for Embedded C (C-SDK) is a collection of C source files under the MIT open source license that can be used in embedded applications to securely connect IoT devices to AWS IoT Core. It contains MQTT client, HTTP client, JSON Parser, AWS IoT Device Shadow, AWS IoT Jobs, and AWS IoT Device Defender libraries. This SDK is distributed in source form, and can be built into customer firmware along with application code, other libraries and an operating system (OS) of your choice. These libraries are only dependent on standard C libraries, so they can be ported to various OS's - from embedded Real Time Operating Systems (RTOS) to Linux/Mac/Windows. You can find sample usage of C-SDK libraries on POSIX systems using OpenSSL (e.g. Linux demos in this repository), and on FreeRTOS using mbedTLS (e.g. FreeRTOS demos in FreeRTOS repository).

For the latest release of C-SDK, please see the section for Releases and Documentation.

C-SDK includes libraries that are part of the FreeRTOS 202012.01 LTS release. Learn more about the FreeRTOS 202012.01 LTS libraries by clicking here.

License

The C-SDK libraries are licensed under the MIT open source license.

Features

C-SDK simplifies access to various AWS IoT services. C-SDK has been tested to work with AWS IoT Core and an open source MQTT broker to ensure interoperability. The AWS IoT Device Shadow, AWS IoT Jobs, and AWS IoT Device Defender libraries are flexible to work with any MQTT client and JSON parser. The MQTT client and JSON parser libraries are offered as choices without being tightly coupled with the rest of the SDK. C-SDK contains the following libraries:

coreMQTT

The coreMQTT library provides the ability to establish an MQTT connection with a broker over a customer-implemented transport layer, which can either be a secure channel like a TLS session (mutually authenticated or server-only authentication) or a non-secure channel like a plaintext TCP connection. This MQTT connection can be used for performing publish operations to MQTT topics and subscribing to MQTT topics. The library provides a mechanism to register customer-defined callbacks for receiving incoming PUBLISH, acknowledgement and keep-alive response events from the broker. The library has been refactored for memory optimization and is compliant with the MQTT 3.1.1 standard. It has no dependencies on any additional libraries other than the standard C library, a customer-implemented network transport interface, and optionally a customer-implemented platform time function. The refactored design embraces different use-cases, ranging from resource-constrained platforms using only QoS 0 MQTT PUBLISH messages to resource-rich platforms using QoS 2 MQTT PUBLISH over TLS connections.

See memory requirements for the latest release here.

coreHTTP

The coreHTTP library provides the ability to establish an HTTP connection with a server over a customer-implemented transport layer, which can either be a secure channel like a TLS session (mutually authenticated or server-only authentication) or a non-secure channel like a plaintext TCP connection. The HTTP connection can be used to make "GET" (include range requests), "PUT", "POST" and "HEAD" requests. The library provides a mechanism to register a customer-defined callback for receiving parsed header fields in an HTTP response. The library has been refactored for memory optimization, and is a client implementation of a subset of the HTTP/1.1 standard.

See memory requirements for the latest release here.

coreJSON

The coreJSON library is a JSON parser that strictly enforces the ECMA-404 JSON standard. It provides a function to validate a JSON document, and a function to search for a key and return its value. A search can descend into nested structures using a compound query key. A JSON document validation also checks for illegal UTF8 encodings and illegal Unicode escape sequences.

See memory requirements for the latest release here.

corePKCS11

The corePKCS11 library is an implementation of the PKCS #11 interface (API) that makes it easier to develop applications that rely on cryptographic operations. Only a subset of the PKCS #11 v2.4 standard has been implemented, with a focus on operations involving asymmetric keys, random number generation, and hashing.

The Cryptoki or PKCS #11 standard defines a platform-independent API to manage and use cryptographic tokens. The name, "PKCS #11", is used interchangeably to refer to the API itself and the standard which defines it.

The PKCS #11 API is useful for writing software without taking a dependency on any particular implementation or hardware. By writing against the PKCS #11 standard interface, code can be used interchangeably with multiple algorithms, implementations and hardware.

Generally vendors for secure cryptoprocessors such as Trusted Platform Module (TPM), Hardware Security Module (HSM), Secure Element, or any other type of secure hardware enclave, distribute a PKCS #11 implementation with the hardware. The purpose of corePKCS11 mock is therefore to provide a PKCS #11 implementation that allows for rapid prototyping and development before switching to a cryptoprocessor specific PKCS #11 implementation in production devices.

Since the PKCS #11 interface is defined as part of the PKCS #11 specification replacing corePKCS11 with another implementation should require little porting effort, as the interface will not change. The system tests distributed in corePKCS11 repository can be leveraged to verify the behavior of a different implementation is similar to corePKCS11.

See memory requirements for the latest release here.

AWS IoT Device Shadow

The AWS IoT Device Shadow library enables you to store and retrieve the current state one or more shadows of every registered device. A device’s shadow is a persistent, virtual representation of your device that you can interact with from AWS IoT Core even if the device is offline. The device state is captured in its "shadow" is represented as a JSON document. The device can send commands over MQTT to get, update and delete its latest state as well as receive notifications over MQTT about changes in its state. The device’s shadow(s) are uniquely identified by the name of the corresponding "thing", a representation of a specific device or logical entity on the AWS Cloud. See Managing Devices with AWS IoT for more information on IoT "thing". This library supports named shadows, a feature of the AWS IoT Device Shadow service that allows you to create multiple shadows for a single IoT device. More details about AWS IoT Device Shadow can be found in AWS IoT documentation.

The AWS IoT Device Shadow library has no dependencies on additional libraries other than the standard C library. It also doesn’t have any platform dependencies, such as threading or synchronization. It can be used with any MQTT library and any JSON library (see demos with coreMQTT and coreJSON).

See memory requirements for the latest release here.

AWS IoT Jobs

The AWS IoT Jobs library enables you to interact with the AWS IoT Jobs service which notifies one or more connected devices of a pending “Job”. A Job can be used to manage your fleet of devices, update firmware and security certificates on your devices, or perform administrative tasks such as restarting devices and performing diagnostics. For documentation of the service, please see the AWS IoT Developer Guide. Interactions with the Jobs service use the MQTT protocol. This library provides an API to compose and recognize the MQTT topic strings used by the Jobs service.

The AWS IoT Jobs library has no dependencies on additional libraries other than the standard C library. It also doesn’t have any platform dependencies, such as threading or synchronization. It can be used with any MQTT library and any JSON library (see demos with libmosquitto and coreJSON).

See memory requirements for the latest release here.

AWS IoT Device Defender

The AWS IoT Device Defender library enables you to interact with the AWS IoT Device Defender service to continuously monitor security metrics from devices for deviations from what you have defined as appropriate behavior for each device. If something doesn’t look right, AWS IoT Device Defender sends out an alert so you can take action to remediate the issue. More details about Device Defender can be found in AWS IoT Device Defender documentation. This library supports custom metrics, a feature that helps you monitor operational health metrics that are unique to your fleet or use case. For example, you can define a new metric to monitor the memory usage or CPU usage on your devices.

The AWS IoT Device Defender library has no dependencies on additional libraries other than the standard C library. It also doesn’t have any platform dependencies, such as threading or synchronization. It can be used with any MQTT library and any JSON library (see demos with coreMQTT and coreJSON).

See memory requirements for the latest release here.

AWS IoT Over-the-air Update

The AWS IoT Over-the-air Update (OTA) library enables you to manage the notification of a newly available update, download the update, and perform cryptographic verification of the firmware update. Using the OTA library, you can logically separate firmware updates from the application running on your devices. You can also use the library to send other files (e.g. images, certificates) to one or more devices registered with AWS IoT. More details about OTA library can be found in AWS IoT Over-the-air Update documentation.

The AWS IoT Over-the-air Update library has a dependency on coreJSON for parsing of JSON job document and tinyCBOR for decoding encoded data streams, other than the standard C library. It can be used with any MQTT library, HTTP library, and operating system (e.g. Linux, FreeRTOS) (see demos with coreMQTT and coreHTTP over Linux).

See memory requirements for the latest release here.

AWS IoT Fleet Provisioning

The AWS IoT Fleet Provisioning library enables you to interact with the AWS IoT Fleet Provisioning MQTT APIs in order to provison IoT devices without preexisting device certificates. With AWS IoT Fleet Provisioning, devices can securely receive unique device certificates from AWS IoT when they connect for the first time. For an overview of all provisioning options offered by AWS IoT, see device provisioning documentation. For details about Fleet Provisioning, refer to the AWS IoT Fleet Provisioning documentation.

See memory requirements for the latest release here.

AWS SigV4

The AWS SigV4 library enables you to sign HTTP requests with Signature Version 4 Signing Process. Signature Version 4 (SigV4) is the process to add authentication information to HTTP requests to AWS services. For security, most requests to AWS must be signed with an access key. The access key consists of an access key ID and secret access key.

See memory requirements for the latest release here.

backoffAlgorithm

The backoffAlgorithm library is a utility library to calculate backoff period using an exponential backoff with jitter algorithm for retrying network operations (like failed network connection with server). This library uses the "Full Jitter" strategy for the exponential backoff with jitter algorithm. More information about the algorithm can be seen in the Exponential Backoff and Jitter AWS blog.

Exponential backoff with jitter is typically used when retrying a failed connection or network request to the server. An exponential backoff with jitter helps to mitigate the failed network operations with servers, that are caused due to network congestion or high load on the server, by spreading out retry requests across multiple devices attempting network operations. Besides, in an environment with poor connectivity, a client can get disconnected at any time. A backoff strategy helps the client to conserve battery by not repeatedly attempting reconnections when they are unlikely to succeed.

The backoffAlgorithm library has no dependencies on libraries other than the standard C library.

See memory requirements for the latest release here.

Sending metrics to AWS IoT

When establishing a connection with AWS IoT, users can optionally report the Operating System, Hardware Platform and MQTT client version information of their device to AWS. This information can help AWS IoT provide faster issue resolution and technical support. If users want to report this information, they can send a specially formatted string (see below) in the username field of the MQTT CONNECT packet.

Format

The format of the username string with metrics is:

<Actual_Username>?SDK=<OS_Name>&Version=<OS_Version>&Platform=<Hardware_Platform>&MQTTLib=<MQTT_Library_name>@<MQTT_Library_version>

Where

  • is the actual username used for authentication, if username and password are used for authentication. When username and password based authentication is not used, this is an empty value.
  • is the Operating System the application is running on (e.g. Ubuntu)
  • is the version number of the Operating System (e.g. 20.10)
  • is the Hardware Platform the application is running on (e.g. RaspberryPi)
  • is the MQTT Client library being used (e.g. coreMQTT)
  • is the version of the MQTT Client library being used (e.g. 1.1.0)

Example

  • Actual_Username = “iotuser”, OS_Name = Ubuntu, OS_Version = 20.10, Hardware_Platform_Name = RaspberryPi, MQTT_Library_Name = coremqtt, MQTT_Library_version = 1.1.0. If username is not used, then “iotuser” can be removed.
/* Username string:
 * iotuser?SDK=Ubuntu&Version=20.10&Platform=RaspberryPi&MQTTLib=coremqtt@1.1.0
 */

#define OS_NAME                   "Ubuntu"
#define OS_VERSION                "20.10"
#define HARDWARE_PLATFORM_NAME    "RaspberryPi"
#define MQTT_LIB                  "coremqtt@1.1.0"

#define USERNAME_STRING           "iotuser?SDK=" OS_NAME "&Version=" OS_VERSION "&Platform=" HARDWARE_PLATFORM_NAME "&MQTTLib=" MQTT_LIB
#define USERNAME_STRING_LENGTH    ( ( uint16_t ) ( sizeof( USERNAME_STRING ) - 1 ) )

MQTTConnectInfo_t connectInfo;
connectInfo.pUserName = USERNAME_STRING;
connectInfo.userNameLength = USERNAME_STRING_LENGTH;
mqttStatus = MQTT_Connect( pMqttContext, &connectInfo, NULL, CONNACK_RECV_TIMEOUT_MS, pSessionPresent );

Versioning

C-SDK releases will now follow a date based versioning scheme with the format YYYYMM.NN, where:

  • Y represents the year.
  • M represents the month.
  • N represents the release order within the designated month (00 being the first release).

For example, a second release in June 2021 would be 202106.01. Although the SDK releases have moved to date-based versioning, each library within the SDK will still retain semantic versioning. In semantic versioning, the version number itself (X.Y.Z) indicates whether the release is a major, minor, or point release. You can use the semantic version of a library to assess the scope and impact of a new release on your application.

Releases and Documentation

All of the released versions of the C-SDK libraries are available as git tags. For example, the last release of the v3 SDK version is available at tag 3.1.2.

202108.00

API documentation of 202108.00 release

This release introduces the refactored AWS IoT Fleet Provisioning library and the new AWS SigV4 library.

Additionally, this release brings minor version updates in the AWS IoT Over-the-Air Update and corePKCS11 libraries.

202103.00

API documentation of 202103.00 release

This release includes a major update to the APIs of the AWS IoT Over-the-air Update library.

Additionally, AWS IoT Device Shadow library introduces a minor update by adding support for named shadow, a feature of the AWS IoT Device Shadow service that allows you to create multiple shadows for a single IoT device. AWS IoT Jobs library introduces a minor update by introducing macros for $next job ID and compile-time generation of topic strings. AWS IoT Device Defender library introduces a minor update that adds macros to API for custom metrics feature of AWS IoT Device Defender service.

corePKCS11 also introduces a patch update by removing the pkcs11configPAL_DESTROY_SUPPORTED config and mbedTLS platform abstraction layer of DestroyObject. Lastly, no code changes are introduced for backoffAlgorithm, coreHTTP, coreMQTT, and coreJSON; however, patch updates are made to improve documentation and CI.

202012.01

API documentation of 202012.01 release

This release includes AWS IoT Over-the-air Update(Release Candidate), backoffAlgorithm, and PKCS #11 libraries. Additionally, there is a major update to the coreJSON and coreHTTP APIs. All libraries continue to undergo code quality checks (e.g. MISRA-C compliance), and Coverity static analysis. In addition, all libraries except AWS IoT Over-the-air Update and backoffAlgorithm undergo validation of memory safety with the C Bounded Model Checker (CBMC) automated reasoning tool.

202011.00

API documentation of 202011.00 release

This release includes refactored HTTP client, AWS IoT Device Defender, and AWS IoT Jobs libraries. Additionally, there is a major update to the coreJSON API. All libraries continue to undergo code quality checks (e.g. MISRA-C compliance), Coverity static analysis, and validation of memory safety with the C Bounded Model Checker (CBMC) automated reasoning tool.

202009.00

API documentation of 202009.00 release

This release includes refactored MQTT, JSON Parser, and AWS IoT Device Shadow libraries for optimized memory usage and modularity. These libraries are included in the SDK via Git submoduling. These libraries have gone through code quality checks including verification that no function has a GNU Complexity score over 8, and checks against deviations from mandatory rules in the MISRA coding standard. Deviations from the MISRA C:2012 guidelines are documented under MISRA Deviations. These libraries have also undergone both static code analysis from Coverity static analysis, and validation of memory safety and data structure invariance through the CBMC automated reasoning tool.

If you are upgrading from v3.x API of the C-SDK to the 202009.00 release, please refer to Migration guide from v3.1.2 to 202009.00 and newer releases. If you are using the C-SDK v4_beta_deprecated branch, note that we will continue to maintain this branch for critical bug fixes and security patches but will not add new features to it. See the C-SDK v4_beta_deprecated branch README for additional details.

v3.1.2

Details available here.

Porting Guide for 202009.00 and newer releases

All libraries depend on the ISO C90 standard library and additionally on the stdint.h library for fixed-width integers, including uint8_t, int8_t, uint16_t, uint32_t and int32_t, and constant macros like UINT16_MAX. If your platform does not support the stdint.h library, definitions of the mentioned fixed-width integer types will be required for porting any C-SDK library to your platform.

Porting coreMQTT

Guide for porting coreMQTT library to your platform is available here.

Porting coreHTTP

Guide for porting coreHTTP library is available here.

Porting AWS IoT Device Shadow

Guide for porting AWS IoT Device Shadow library is available here.

Porting AWS IoT Device Defender

Guide for porting AWS IoT Device Defender library is available here.

Porting AWS IoT Over-the-air Update

Guide for porting OTA library to your platform is available here.

Migration guide from v3.1.2 to 202009.00 and newer releases

MQTT Migration

Migration guide for MQTT library is available here.

Shadow Migration

Migration guide for Shadow library is available here.

Jobs Migration

Migration guide for Jobs library is available here.

Branches

main branch

The main branch hosts the continuous development of the AWS IoT Embedded C SDK (C-SDK) libraries. Please be aware that the development at the tip of the main branch is continuously in progress, and may have bugs. Consider using the tagged releases of the C-SDK for production ready software.

v4_beta_deprecated branch (formerly named v4_beta)

The v4_beta_deprecated branch contains a beta version of the C-SDK libraries, which is now deprecated. This branch was earlier named as v4_beta, and was renamed to v4_beta_deprecated. The libraries in this branch will not be released. However, critical bugs will be fixed and tested. No new features will be added to this branch.

Getting Started

Cloning

This repository uses Git Submodules to bring in the C-SDK libraries (eg, MQTT ) and third-party dependencies (eg, mbedtls for POSIX platform transport layer). Note: If you download the ZIP file provided by GitHub UI, you will not get the contents of the submodules (The ZIP file is also not a valid git repository). If you download from the 202012.00 Release Page page, you will get the entire repository (including the submodules) in the ZIP file, aws-iot-device-sdk-embedded-c-202012.00.zip. To clone the latest commit to main branch using HTTPS:

git clone --recurse-submodules https://github.com/aws/aws-iot-device-sdk-embedded-C.git

Using SSH:

git clone --recurse-submodules git@github.com:aws/aws-iot-device-sdk-embedded-C.git

If you have downloaded the repo without using the --recurse-submodules argument, you need to run:

git submodule update --init --recursive

When building with CMake, submodules are also recursively cloned automatically. However, -DBUILD_CLONE_SUBMODULES=0 can be passed as a CMake flag to disable this functionality. This is useful when you'd like to build CMake while using a different commit from a submodule.

Configuring Demos

The libraries in this SDK are not dependent on any operating system. However, the demos for the libraries in this SDK are built and tested on a Linux platform. The demos build with CMake, a cross-platform build tool.

Prerequisites

  • CMake 3.2.0 or any newer version for utilizing the build system of the repository.
  • C90 compiler such as gcc
    • Due to the use of mbedtls in corePKCS11, a C99 compiler is required if building the PKCS11 demos or the CMake install target.
  • Although not a part of the ISO C90 standard, stdint.h is required for fixed-width integer types that include uint8_t, int8_t, uint16_t, uint32_t and int32_t, and constant macros like UINT16_MAX, while stdbool.h is required for boolean parameters in coreMQTT. For compilers that do not provide these header files, coreMQTT provides the files stdint.readme and stdbool.readme, which can be renamed to stdint.h and stdbool.h, respectively, to provide the required type definitions.
  • A supported operating system. The ports provided with this repo are expected to work with all recent versions of the following operating systems, although we cannot guarantee the behavior on all systems.
    • Linux system with POSIX sockets, threads, RT, and timer APIs. (We have tested on Ubuntu 18.04).

Build Dependencies

The follow table shows libraries that need to be installed in your system to run certain demos. If a dependency is not installed and cannot be built from source, demos that require that dependency will be excluded from the default all target.

DependencyVersionUsage
OpenSSL1.1.0 or laterAll TLS demos and tests with the exception of PKCS11
Mosquitto Client1.4.10 or laterAWS IoT Jobs Mosquitto demo

AWS IoT Account Setup

You need to setup an AWS account and access the AWS IoT console for running the AWS IoT Device Shadow library, AWS IoT Device Defender library, AWS IoT Jobs library, AWS IoT OTA library and coreHTTP S3 download demos. Also, the AWS account can be used for running the MQTT mutual auth demo against AWS IoT broker. Note that running the AWS IoT Device Defender, AWS IoT Jobs and AWS IoT Device Shadow library demos require the setup of a Thing resource for the device running the demo. Follow the links to:

The MQTT Mutual Authentication and AWS IoT Shadow demos include example AWS IoT policy documents to run each respective demo with AWS IoT. You may use the MQTT Mutual auth and Shadow example policies by replacing [AWS_REGION] and [AWS_ACCOUNT_ID] with the strings of your region and account identifier. While the IoT Thing name and MQTT client identifier do not need to match for the demos to run, the example policies have the Thing name and client identifier identical as per AWS IoT best practices.

It can be very helpful to also have the AWS Command Line Interface tooling installed.

Configuring mutual authentication demos of MQTT and HTTP

You can pass the following configuration settings as command line options in order to run the mutual auth demos. Make sure to run the following command in the root directory of the C-SDK:

## optionally find your-aws-iot-endpoint from the command line
aws iot describe-endpoint --endpoint-type iot:Data-ATS
cmake -S . -Bbuild
-DAWS_IOT_ENDPOINT="<your-aws-iot-endpoint>" -DCLIENT_CERT_PATH="<your-client-certificate-path>" -DCLIENT_PRIVATE_KEY_PATH="<your-client-private-key-path>"

In order to set these configurations manually, edit demo_config.h in demos/mqtt/mqtt_demo_mutual_auth/ and demos/http/http_demo_mutual_auth/ to #define the following:

  • Set AWS_IOT_ENDPOINT to your custom endpoint. This is found on the Settings page of the AWS IoT Console and has a format of ABCDEFG1234567.iot.<aws-region>.amazonaws.com where <aws-region> can be an AWS region like us-east-2.
    • Optionally, it can also be found with the AWS CLI command aws iot describe-endpoint --endpoint-type iot:Data-ATS.
  • Set CLIENT_CERT_PATH to the path of the client certificate downloaded when setting up the device certificate in AWS IoT Account Setup.
  • Set CLIENT_PRIVATE_KEY_PATH to the path of the private key downloaded when setting up the device certificate in AWS IoT Account Setup.

It is possible to configure ROOT_CA_CERT_PATH to any PEM-encoded Root CA Certificate. However, this is optional because CMake will download and set it to AmazonRootCA1.pem when unspecified.

Configuring AWS IoT Device Defender and AWS IoT Device Shadow demos

To build the AWS IoT Device Defender and AWS IoT Device Shadow demos, you can pass the following configuration settings as command line options. Make sure to run the following command in the root directory of the C-SDK:

cmake -S . -Bbuild -DAWS_IOT_ENDPOINT="<your-aws-iot-endpoint>" -DROOT_CA_CERT_PATH="<your-path-to-amazon-root-ca>" -DCLIENT_CERT_PATH="<your-client-certificate-path>" -DCLIENT_PRIVATE_KEY_PATH="<your-client-private-key-path>" -DTHING_NAME="<your-registered-thing-name>"

An Amazon Root CA certificate can be downloaded from here.

In order to set these configurations manually, edit demo_config.h in the demo folder to #define the following:

  • Set AWS_IOT_ENDPOINT to your custom endpoint. This is found on the Settings page of the AWS IoT Console and has a format of ABCDEFG1234567.iot.us-east-2.amazonaws.com.
  • Set ROOT_CA_CERT_PATH to the path of the root CA certificate downloaded when setting up the device certificate in AWS IoT Account Setup.
  • Set CLIENT_CERT_PATH to the path of the client certificate downloaded when setting up the device certificate in AWS IoT Account Setup.
  • Set CLIENT_PRIVATE_KEY_PATH to the path of the private key downloaded when setting up the device certificate in AWS IoT Account Setup.
  • Set THING_NAME to the name of the Thing created in AWS IoT Account Setup.

Configuring the AWS IoT Fleet Provisioning demo

To build the AWS IoT Fleet Provisioning Demo, you can pass the following configuration settings as command line options. Make sure to run the following command in the root directory of the C-SDK:

cmake -S . -Bbuild -DAWS_IOT_ENDPOINT="<your-aws-iot-endpoint>" -DROOT_CA_CERT_PATH="<your-path-to-amazon-root-ca>" -DCLAIM_CERT_PATH="<your-claim-certificate-path>" -DCLAIM_PRIVATE_KEY_PATH="<your-claim-private-key-path>" -DPROVISIONING_TEMPLATE_NAME="<your-template-name>" -DDEVICE_SERIAL_NUMBER="<your-serial-number>"

An Amazon Root CA certificate can be downloaded from here.

To create a provisioning template and claim credentials, sign into your AWS account and visit here. Make sure to enable the "Use the AWS IoT registry to manage your device fleet" option. Once you have created the template and credentials, modify the claim certificate's policy to match the sample policy.

In order to set these configurations manually, edit demo_config.h in the demo folder to #define the following:

  • Set AWS_IOT_ENDPOINT to your custom endpoint. This is found on the Settings page of the AWS IoT Console and has a format of ABCDEFG1234567.iot.us-east-2.amazonaws.com.
  • Set ROOT_CA_CERT_PATH to the path of the root CA certificate downloaded when setting up the device certificate in AWS IoT Account Setup.
  • Set CLAIM_CERT_PATH to the path of the claim certificate downloaded when setting up the template and claim credentials.
  • Set CLAIM_PRIVATE_KEY_PATH to the path of the private key downloaded when setting up the template and claim credentials.
  • Set PROVISIONING_TEMPLATE_NAME to the name of the provisioning template created.
  • Set DEVICE_SERIAL_NUMBER to an arbitrary string representing a device identifier.

Configuring the S3 demos

You can pass the following configuration settings as command line options in order to run the S3 demos. Make sure to run the following command in the root directory of the C-SDK:

cmake -S . -Bbuild -DS3_PRESIGNED_GET_URL="s3-get-url" -DS3_PRESIGNED_PUT_URL="s3-put-url"

S3_PRESIGNED_PUT_URL is only needed for the S3 upload demo.

In order to set these configurations manually, edit demo_config.h in demos/http/http_demo_s3_download_multithreaded, and demos/http/http_demo_s3_upload to #define the following:

  • Set S3_PRESIGNED_GET_URL to a S3 presigned URL with GET access.
  • Set S3_PRESIGNED_PUT_URL to a S3 presigned URL with PUT access.

You can generate the presigned urls using demos/http/common/src/presigned_urls_gen.py. More info can be found here.

Configure S3 Download HTTP Demo using SigV4 Library:

Refer this demos/http/http_demo_s3_download/README.md to follow the steps needed to configure and run the S3 Download HTTP Demo using SigV4 Library that generates the authorization HTTP header needed to authenticate the HTTP requests send to S3.

Setup for AWS IoT Jobs demo

  1. The demo requires the Linux platform to contain curl and libmosquitto. On a Debian platform, these dependencies can be installed with:
    apt install curl libmosquitto-dev

If the platform does not contain the libmosquitto library, the demo will build the library from source.

libmosquitto 1.4.10 or any later version of the first major release is required to run this demo.

  1. A job that specifies the URL to download for the demo needs to be created on the AWS account for the Thing resource that will be used by the demo.
    The job can be created directly from the AWS IoT console or using the aws cli tool.

The following creates a job that specifies a Linux Kernel link for downloading.

 aws iot create-job \
        --job-id 'job_1' \
        --targets arn:aws:iot:us-west-2:<account-id>:thing/<thing-name> \
        --document '{"url":"https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.8.5.tar.xz"}'

Prerequisites for the AWS Over-The-Air Update (OTA) demos

  1. To perform a successful OTA update, you need to complete the prerequisites mentioned here.
  2. A code signing certificate is required to authenticate the update. A code signing certificate based on the SHA-256 ECDSA algorithm will work with the current demos. An example of how to generate this kind of certificate can be found here.

Scheduling an OTA Update Job

After you build and run the initial executable you will have to create another executable and schedule an OTA update job with this image.

  1. Increase the version of the application by setting macro APP_VERSION_BUILD in demos/ota/ota_demo_core_[mqtt/http]/demo_config.h to a different version than what is running.
  2. Rebuild the application using the build steps below into a different directory, say build-dir-2.
  3. Rename the demo executable to reflect the change, e.g. mv ota_demo_core_mqtt ota_demo_core_mqtt2
  4. Create an OTA job:
    1. Go to the AWS IoT Core console.
    2. Manage → Jobs → Create → Create a FreeRTOS OTA update job → Select the corresponding name for your device from the thing list.
    3. Sign a new firmware → Create a new profile → Select any SHA-ECDSA signing platform → Upload the code signing certificate(from prerequisites) and provide its path on the device.
    4. Select the image → Select the bucket you created during the prerequisite steps → Upload the binary build-dir-2/bin/ota_demo2.
    5. The path on device should be the absolute path to place the executable and the binary name: e.g. /home/ubuntu/aws-iot-device-sdk-embedded-C-staging/build-dir/bin/ota_demo_core_mqtt2.
    6. Select the IAM role created during the prerequisite steps.
    7. Create the Job.
  5. Run the initial executable again with the following command: sudo ./ota_demo_core_mqtt or sudo ./ota_demo_core_http.
  6. After the initial executable has finished running, go to the directory where the downloaded firmware image resides which is the path name used when creating an OTA job.
  7. Change the permissions of the downloaded firmware to make it executable, as it may be downloaded with read (user default) permissions only: chmod 775 ota_demo_core_mqtt2
  8. Run the downloaded firmware image with the following command: sudo ./ota_demo_core_mqtt2

Building and Running Demos

Before building the demos, ensure you have installed the prerequisite software. On Ubuntu 18.04 and 20.04, gcc, cmake, and OpenSSL can be installed with:

sudo apt install build-essential cmake libssl-dev

Build a single demo

  • Go to the root directory of the C-SDK.
  • Run cmake to generate the Makefiles: cmake -S . -Bbuild && cd build
  • Choose a demo from the list below or alternatively, run make help | grep demo:
defender_demo
http_demo_basic_tls
http_demo_mutual_auth
http_demo_plaintext
http_demo_s3_download
http_demo_s3_download_multithreaded
http_demo_s3_upload
jobs_demo_mosquitto
mqtt_demo_basic_tls
mqtt_demo_mutual_auth
mqtt_demo_plaintext
mqtt_demo_serializer
mqtt_demo_subscription_manager
ota_demo_core_http
ota_demo_core_mqtt
pkcs11_demo_management_and_rng
pkcs11_demo_mechanisms_and_digests
pkcs11_demo_objects
pkcs11_demo_sign_and_verify
shadow_demo_main
  • Replace demo_name with your desired demo then build it: make demo_name
  • Go to the build/bin directory and run any demo executables from there.

Build all configured demos

  • Go to the root directory of the C-SDK.
  • Run cmake to generate the Makefiles: cmake -S . -Bbuild && cd build
  • Run this command to build all configured demos: make
  • Go to the build/bin directory and run any demo executables from there.

Running corePKCS11 demos

The corePKCS11 demos do not require any AWS IoT resources setup, and are standalone. The demos build upon each other to introduce concepts in PKCS #11 sequentially. Below is the recommended order.

  1. pkcs11_demo_management_and_rng
  2. pkcs11_demo_mechanisms_and_digests
  3. pkcs11_demo_objects
  4. pkcs11_demo_sign_and_verify
    1. Please note that this demo requires the private and public key generated from pkcs11_demo_objects to be in the directory the demo is executed from.

Alternative option of Docker containers for running demos locally

Install Docker:

curl -fsSL https://get.docker.com -o get-docker.sh

sh get-docker.sh

Installing Mosquitto to run MQTT demos locally

The following instructions have been tested on an Ubuntu 18.04 environment with Docker and OpenSSL installed.

Download the official Docker image for Mosquitto 1.6.14. This version is deliberately chosen so that the Docker container can load certificates from the host system. Any version after 1.6.14 will drop privileges as soon as the configuration file has been read (before TLS certificates are loaded).

docker pull eclipse-mosquitto:1.6.14

If a Mosquitto broker with TLS communication needs to be run, ignore this step and proceed to the next step. A Mosquitto broker with plain text communication can be run by executing the command below.

docker run -it -p 1883:1883 --name mosquitto-plain-text eclipse-mosquitto:1.6.14

Set BROKER_ENDPOINT defined in demos/mqtt/mqtt_demo_plaintext/demo_config.h to localhost.

Ignore the remaining steps unless a Mosquitto broker with TLS communication also needs to be run.

For TLS communication with Mosquitto broker, server and CA credentials need to be created. Use OpenSSL commands to generate the credentials for the Mosquitto server.

# Generate CA key and certificate. Provide the Subject field information as appropriate for CA certificate.
openssl req -x509 -nodes -sha256 -days 365 -newkey rsa:2048 -keyout ca.key -out ca.crt
# Generate server key and certificate.# Provide the Subject field information as appropriate for Server certificate. Make sure the Common Name (CN) field is different from the root CA certificate.
openssl req -nodes -sha256 -new -keyout server.key -out server.csr # Sign with the CA cert.
openssl x509 -req -sha256 -in server.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out server.crt -days 365

Note: Make sure to use different Common Name (CN) detail between the CA and server certificates; otherwise, SSL handshake fails with exactly same Common Name (CN) detail in both the certificates.

port 8883

cafile /mosquitto/config/ca.crt
certfile /mosquitto/config/server.crt
keyfile /mosquitto/config/server.key

# Use this option for TLS mutual authentication (where client will provide CA signed certificate)
#require_certificate true
tls_version tlsv1.2
#use_identity_as_username true

Create a mosquitto.conf file to use port 8883 (for TLS communication) and providing path to the generated credentials.

Run the docker container from the local directory containing the generated credential and mosquitto.conf files.

docker run -it -p 8883:8883 -v $(pwd):/mosquitto/config/ --name mosquitto-basic-tls eclipse-mosquitto:1.6.14

Update demos/mqtt/mqtt_demo_basic_tls/demo_config.h to the following:
Set BROKER_ENDPOINT to localhost.
Set ROOT_CA_CERT_PATH to the absolute path of the CA certificate created in step 4. for the local Mosquitto server.

Installing httpbin to run HTTP demos locally

Run httpbin through port 80:

docker pull kennethreitz/httpbin
docker run -p 80:80 kennethreitz/httpbin

SERVER_HOST defined in demos/http/http_demo_plaintext/demo_config.h can now be set to localhost.

To run http_demo_basic_tls, download ngrok in order to create an HTTPS tunnel to the httpbin server currently hosted on port 80:

./ngrok http 80 # May have to use ./ngrok.exe depending on OS or filename of the executable

ngrok will provide an https link that can be substituted in demos/http/http_demo_basic_tls/demo_config.h and has a format of https://ABCDEFG12345.ngrok.io.

Set SERVER_HOST in demos/http/http_demo_basic_tls/demo_config.h to the https link provided by ngrok, without https:// preceding it.

You must also download the Root CA certificate provided by the ngrok https link and set ROOT_CA_CERT_PATH in demos/http/http_demo_basic_tls/demo_config.h to the file path of the downloaded certificate.

Installation

The C-SDK libraries and platform abstractions can be installed to a file system through CMake. To do so, run the following command in the root directory of the C-SDK. Note that installation is not required to run any of the demos.

cmake -S . -Bbuild -DBUILD_DEMOS=0 -DBUILD_TESTS=0
cd build
sudo make install

Note that because make install will automatically build the all target, it may be useful to disable building demos and tests with -DBUILD_DEMOS=0 -DBUILD_TESTS=0 unless they have already been configured. Super-user permissions may be needed if installing to a system include or system library path.

To install only a subset of all libraries, pass -DINSTALL_LIBS to install only the libraries you need. By default, all libraries will be installed, but you may exclude any library that you don't need from this list:

-DINSTALL_LIBS="DEFENDER;SHADOW;JOBS;OTA;OTA_HTTP;OTA_MQTT;BACKOFF_ALGORITHM;HTTP;JSON;MQTT;PKCS"

By default, the install path will be in the project directory of the SDK. You can also set -DINSTALL_TO_SYSTEM=1 to install to the system path for headers and libraries in your OS (e.g. /usr/local/include & /usr/local/lib for Linux).

Upon entering make install, the location of each library will be specified first followed by the location of all installed headers:

-- Installing: /usr/local/lib/libaws_iot_defender.so
-- Installing: /usr/local/lib/libaws_iot_shadow.so
...
-- Installing: /usr/local/include/aws/defender.h
-- Installing: /usr/local/include/aws/defender_config_defaults.h
-- Installing: /usr/local/include/aws/shadow.h
-- Installing: /usr/local/include/aws/shadow_config_defaults.h

You may also set an installation path of your choice by passing the following flags through CMake. Make sure to run the following command in the root directory of the C-SDK:

cmake -S . -Bbuild -DBUILD_DEMOS=0 -DBUILD_TESTS=0 \
-DCSDK_HEADER_INSTALL_PATH="/header/path" -DCSDK_LIB_INSTALL_PATH="/lib/path"
cd build
sudo make install

POSIX platform abstractions are used together with the C-SDK libraries in the demos. By default, these abstractions are also installed but can be excluded by passing the flag: -DINSTALL_PLATFORM_ABSTRACTIONS=0.

Lastly, a custom config path for any specific library can also be specified through the following CMake flags, allowing libraries to be compiled with a config of your choice:

-DDEFENDER_CUSTOM_CONFIG_DIR="defender-config-directory"
-DSHADOW_CUSTOM_CONFIG_DIR="shadow-config-directory"
-DJOBS_CUSTOM_CONFIG_DIR="jobs-config-directory"
-DOTA_CUSTOM_CONFIG_DIR="ota-config-directory"
-DHTTP_CUSTOM_CONFIG_DIR="http-config-directory"
-DJSON_CUSTOM_CONFIG_DIR="json-config-directory"
-DMQTT_CUSTOM_CONFIG_DIR="mqtt-config-directory"
-DPKCS_CUSTOM_CONFIG_DIR="pkcs-config-directory"

Note that the file name of the header should not be included in the directory.

Generating Documentation

Note: For pre-generated documentation, please visit Releases and Documentation section.

The Doxygen references were created using Doxygen version 1.9.2. To generate the Doxygen pages, use the provided Python script at tools/doxygen/generate_docs.py. Please ensure that each of the library submodules under libraries/standard/ and libraries/aws/ are cloned before using this script.

cd <CSDK_ROOT>
git submodule update --init --recursive --checkout
python3 tools/doxygen/generate_docs.py

The generated documentation landing page is located at docs/doxygen/output/html/index.html.

Author: aws
Source code: https://github.com/aws/aws-iot-device-sdk-embedded-C
License: MIT license

#aws 

Entrance i

Entrance i

1590405742

NCERT Solutions for Class 11 Science All subjects|Entrancei

You will learn many new ideas like electricity in physics class 11. The current flow in metals is based on free electrons. In the absence of an electromagnetic field applied to the outside (using a battery), the free electrons move randomly through the metal from one point to another and cause a zero net current .

When connected to a battery, free electrons accelerate due to the electric field generated by the battery and gain speed and energy. However, the passage is not smooth and the electrons collide with the crosslinked ions whose final gain (energy) is the ion. Since we know that body temperature is related to the vibrational energy of these ions, these collisions cause the temperature of the metal to increase. The energy loss of the colliding electrons and their acceleration by the electric field ultimately causes the electrons to drift in a certain direction. (Although the actual movement of the electrons is irregular, the general effect is that the electrons drift.) In addition to this mechanics, the most important part of class 11 physics is where you learn that movement means changing position over time. When a body is at rest, its position does not change over time. But how to describe the position of a body? To do this, we must describe it in relation to another body as a reference.

Rest and movement are therefore relative. A man seated in a car traveling on the highway at 55 km / h is resting relative to a traveling companion while moving relative to a person standing on the highway.

To describe rest and movement, we select a frame of reference, and then describe rest or movement relative to that frame of reference.

There are two types of movements: transnational and rotational.

If a body moves in such a way that it always remains parallel to it throughout the movement, it is translated. When a body moves so that each point on the body maintains a constant distance from a fixed axis in space, the movement is a rotation.

Chapters of Physics class 11 Notes

Chapter 12 Chapter Exam Notes for Class 12 Physics
Chapter 1 - Charges and electric fields
Chapter 2 - Electrostatic potential and capacity
Chapter 3 - Electricity
Chapter 4 - Mobile charge and magnetism
Chapter 5 - Magnetism and matter
Chapter 6 - Electromagnetic induction
Chapter 7 - AC
Chapter 8 - Electromagnetic waves
Chapter 9 - Radiation optics and optical instruments.
Chapter 10 - Wave optics
Chapter 11 - Dual nature of radiation and matter.
Class 12 electricity and electric fields.
Chapter 13 - Hearts
Chapter 14 - Semiconductor electronics: material, components and simple circuits.
Chapter 15 - Communication systems

Why Entrancei for Physics Class 11 Notes

The entry academic team is made up of a team of very experienced teachers who have prepared a special academic resource for physics class 11. We have prepared several sections for class 11 physics for students preparing for JEE and preparing for the CBSE board exam. Our team knows the needs for class 11 physical resources and how to use them. You can get detailed physical notes for class 11 chapter by chapter with additional resolved and unresolved examples. Each chapter of class 11 physics notes consists of one to five exercises with objective questions that improve the learning of the chapters. Ncert solutions for class 11 will help you pass the exam prepared by our academic team. On the same page, you will find an online questionnaire chapter by page for physics in class 11. The model of the online questionnaire is similar to that of exam management. In addition to these resources, you can read important questions for class 11 physics and various segments for class 11 physics formulas. In addition to the resource mentioned above for class 11 physics, you can download documents from the previous year, examples of documents for class 11 physics, key chemical formulas and a list of name reactions in organic chemistry. In the section on chemistry questions, you will find many class 11 physics questions that have been answered using examples.
Source Url: https://bit.ly/2LXEt9O

#physics class 11 notes #ncert solutions for class 11

Lawrence Lesch

Lawrence Lesch

1662107520

Superdom: Better and Simpler ES6 DOM Manipulation

Superdom

You have dom. It has all the DOM virtually within it. Use that power:

// Fetch all the page links
let links = dom.a.href;

// Links open in a new tab
dom.a.target = '_blank';

Only for modern browsers

Getting started

Simply use the CDN via unpkg.com:

<script src="https://unpkg.com/superdom@1"></script>

Or use npm or bower:

npm|bower install superdom --save

Select

It always returns an array with the matched elements. Get all the elements that match the selector:

// Simple element selector into an array
let allLinks = dom.a;

// Loop straight on the selection
dom.a.forEach(link => { ... });

// Combined selector
let importantLinks = dom['a.important'];

There are also some predetermined elements, such as id, class and attr:

// Select HTML Elements by id:
let main = dom.id.main;

// by class:
let buttons = dom.class.button;

// or by attribute:
let targeted = dom.attr.target;
let targeted = dom.attr['target="_blank"'];

Generate

Use it as a function or a tagged template literal to generate DOM fragments:

// Not a typo; tagged template literals
let link = dom`<a href="https://google.com/">Google</a>`;

// It is the same as
let link = dom('<a href="https://google.com/">Google</a>');

Delete elements

Delete a piece of the DOM

// Delete all of the elements with the class .google
delete dom.class.google;   // Is this an ad-block rule?

Attributes

You can easily manipulate attributes right from the dom node. There are some aliases that share the syntax of the attributes such as html and text (aliases for innerHTML and textContent). There are others that travel through the dom such as parent (alias for parentNode) and children. Finally, class behaves differently as explained below.

Get attributes

The fetching will always return an array with the element for each of the matched nodes (or undefined if not there):

// Retrieve all the urls from the page
let urls = dom.a.href;     // #attr-list
  // ['https://google.com', 'https://facebook.com/', ...]

// Get an array of the h2 contents (alias of innerHTML)
let h2s = dom.h2.html;     // #attr-alias
  // ['Level 2 header', 'Another level 2 header', ...]

// Get whether any of the attributes has the value "_blank"
let hasBlank = dom.class.cta.target._blank;    // #attr-value
  // true/false

You also use these:

  • html (alias of innerHTML): retrieve a list of the htmls
  • text (alias of textContent): retrieve a list of the htmls
  • parent (alias of parentNode): travel up one level
  • children: travel down one level

Set attributes

// Set target="_blank" to all links
dom.a.target = '_blank';     // #attr-set

dom.class.tableofcontents.html = `
  <ul class="tableofcontents">
    ${dom.h2.map(h2 => `
      <li>
        <a href="#${h2.id}">
          ${h2.innerHTML}
        </a>
      </li>
    `).join('')}
  </ul>
`;

Remove an attribute

To delete an attribute use the delete keyword:

// Remove all urls from the page
delete dom.a.href;

// Remove all ids
delete dom.a.id;

Classes

It provides an easy way to manipulate the classes.

Get classes

To retrieve whether a particular class is present or not:

// Get an array with true/false for a single class
let isTest = dom.a.class.test;     // #class-one

For a general method to retrieve all classes you can do:

// Get a list of the classes of each matched element
let arrays = dom.a.class;     // #class-arrays
  // [['important'], ['button', 'cta'], ...]

// If you want a plain list with all of the classes:
let flatten = dom.a.class._flat;     // #class-flat
  // ['important', 'button', 'cta', ...]

// And if you just want an string with space-separated classes:
let text = dom.a.class._text;     // #class-text
  // 'important button cta ...'

Add a class

// Add the class 'test' (different ways)
dom.a.class.test = true;    // #class-make-true
dom.a.class = 'test';       // #class-push

Remove a class

// Remove the class 'test'
dom.a.class.test = false;    // #class-make-false

Manipulate

Did we say it returns a simple array?

dom.a.forEach(link => link.innerHTML = 'I am a link');

But what an interesting array it is; indeed we are also proxy'ing it so you can manipulate its sub-elements straight from the selector:

// Replace all of the link's html with 'I am a link'
dom.a.html = 'I am a link';

Of course we might want to manipulate them dynamically depending on the current value. Just pass it a function:

// Append ' ^_^' to all of the links in the page
dom.a.html = html => html + ' ^_^';

// Same as this:
dom.a.forEach(link => link.innerHTML = link.innerHTML + ' ^_^');

Note: this won't work dom.a.html += ' ^_^'; for more than 1 match (for reasons)

Or get into genetics to manipulate the attributes:

dom.a.attr.target = '_blank';

// Only to external sites:
let isOwnPage = el => /^https?\:\/\/mypage\.com/.test(el.getAttribute('href'));
dom.a.attr.target = (prev, i, element) => isOwnPage(element) ? '' : '_blank';

Events

You can also handle and trigger events:

// Handle click events for all <a>
dom.a.on.click = e => ...;

// Trigger click event for all <a>
dom.a.trigger.click;

Testing

We are using Jest as a Grunt task for testing. Install Jest and run in the terminal:

grunt watch

Download Details:

Author: franciscop
Source Code: https://github.com/franciscop/superdom 
License: MIT license

#javascript #es6 #dom 

Entrance i

Entrance i

1590400189

NCERT solutions for class 9 All subjects|Entrancei

Biology (Gk. Bios-life and logos-to speech) is the branch of science that deals with the scientific study of life. It depends on other sciences (such as physics and chemistry) and has therefore become a multidisciplinary and multidimensional scientific branch. Biology is better known as “life sciences” because it seeks to understand how living things interact with other “living” and “non-living” things.
Precisely, biology is research, an ongoing investigation into the nature of life. Biology, being an important branch of science, requires a scientific approach to understand and obtain precise results.

• The term “biology” was coined by Lamarck and Treviranus in 1802.
• Aristotle is known as “father of biology and zoology”.
• Theophrastus is known as the “father of botany”.
• Microorganisms were first observed by A.V. Leeuwenhoek but Louis Pasteur is considered to be the father of microbiology.
• Emil von Behring (Germany) was the first Nobel Prize in physiology and medicine to receive this prize in 1901 for serum therapy against “diphtheria”

Chapters cover in class 9 Biology

Chapter 1 - The fundamental unit of life
This chapter will help you discover the cell as the basic unit of life. Biology experts will give you step-by-step answers to explain concepts like eukaryotic cells, prokaryotic cells, chloroplast, Golgi apparatus, chromosomes, nuclei, etc.

Chapter 2 - Fabrics
Get answers on plant and animal tissue Chapter 2, Tissue. Discover the permanent and meristematic fabrics. Understand the structure of tissues and write precise answers to questions related to this concept.

Chapter 3 - Diversity of living organisms
This chapter explores concepts of biological diversity, such as groups of plants and groups of animals. Find NCERT expert solutions with explanations on angiosperms, bacteria, bryophytes, chordates, non-chordates and more.

Chapter 4 - Why are we sick?
Find out what it means to be healthy and unhealthy. Get complete answers about the causes of the disease and how you can lead a healthy life. In this chapter, learn about diseases, causes of diseases and infectious diseases.

Chapter 5 - Natural Resources
Understand the importance of resources such as air, water and soil. Write answers about geochemical cycles in nature. This chapter also deals with types of pollution and methods of pollution control to avoid possible damage.

Chapter 6 - Improving Food Resources
Explore concepts such as animal husbandry, the use of fertilizers, and ways to protect crops from pests. Find answers to questions about crop improvement, crop protection, agricultural production, etc. Also discover the basic concepts and the importance of organic farming in this chapter on biology.

Why Entrancei for CBSE class 9 Biology

The entry academic team is made up of a team of very experienced teachers who have prepared a dedicated academic resource for class 9 biology. Our team understands the resource requirements for class 9 biology and its use. You can get a detailed chapter of class 9 biology notes with the addition of resolved and unresolved examples. Each chapter of class 9 biology notes consists of one to 5 exercises with objective type questions that have improved your learning from the chapters. NCERT solutions for class 9 will help you excel in the exam prepared by our academic team. On the same page, you will get an online quiz for biology class 9. The model of the online questionnaire is similar to that of the body of the exam. In addition to these resources, you can refer to the Important questions for class 9 biology and to the different segments for class 9 biology formulas.
Source Url: https://bit.ly/2TySs9W

#class 9 biology #ncert solutions for class 9

Uriah Dietrich

Uriah Dietrich

1618449987

How To Build A Data Science Career In 2021

For this week’s data science career interview, we got in touch with Dr Suman Sanyal, Associate Professor of Computer Science and Engineering at NIIT University. In this interview, Dr Sanyal shares his insights on how universities can contribute to this highly promising sector and what aspirants can do to build a successful data science career.

With industry-linkage, technology and research-driven seamless education, NIIT University has been recognised for addressing the growing demand for data science experts worldwide with its industry-ready courses. The university has recently introduced B.Tech in Data Science course, which aims to deploy data sets models to solve real-world problems. The programme provides industry-academic synergy for the students to establish careers in data science, artificial intelligence and machine learning.

“Students with skills that are aligned to new-age technology will be of huge value. The industry today wants young, ambitious students who have the know-how on how to get things done,” Sanyal said.

#careers # #data science aspirant #data science career #data science career intervie #data science education #data science education marke #data science jobs #niit university data science