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The completion and opening ceremony of the Beidou-3 global satellite navigation system was held in Beijing on the morning of July 31.
It was learned on July 29 that the 55th Beidou satellite navigation system (Beidou-3 geostationary orbit satellite) has completed in-orbit testing and network access evaluation, and has officially entered the network recently, using the ranging code number 61 to provide positioning and navigation timing. service. The satellite was developed by the China Academy of Space Technology and launched at the Xichang Satellite Launch Center on June 23, 2020.

china  Beidou-3 global satellite

Big Dipper has five abilities

The short message communication function is a "unique skill"

The Beidou satellite navigation system is an important space infrastructure independently constructed and operated by my country. It is also the largest complex space system with the largest scale, the widest coverage and the highest service performance requirements in my country so far.

Speaking of Beidou, the first reaction of many people is "navigation and positioning." Real-time navigation and fast positioning are the most basic functions of a satellite navigation system. In addition, Beidou also has three characteristic functions: precise timing, position reporting and short message communication.

"The Beidou satellite itself is a time service system in our country." Lu Xiaochun, deputy director of the National Time Service Center of the Chinese Academy of Sciences, said that the accuracy of the satellite-borne rubidium atomic clock on the Beidou-3 satellite is at the international leading level, reaching 5/10 billionths of a second per day. At present, this function has been widely used in communication, power, financial and other systems.

The position report function is closely related to the characteristics of Beidou's "active positioning". Active positioning is a major innovation of China's Beidou. It uses radio measurement technology and two geosynchronous orbit satellites to work together. It can not only answer the user "Where am I", but also tell related parties who follow the user's whereabouts "Where are you". Widely used in search and rescue, fishery and other fields, it is a "clairvoyance" to ensure people's livelihood safety.

The short message communication function is the "unique skill" of the Beidou system. Navigation satellites and communication satellites are two types of satellites, but Beidou navigation satellites have additional communication functions. Wang Bo, deputy secretary-general of the China Satellite Navigation and Positioning Association, said that Beidou users can not only know their location through the terminal, but also tell others about their situation through short messages. This function is essential in areas where there is no network coverage such as deserts, oceans, deep mountains, and forests, or when disasters occur and communications are blocked.

In the Beidou No. 3 system, the ability of short message communication has been significantly improved. The ability to send information has increased from 120 Chinese characters at a time to 1,200 Chinese characters. It is widely used in many fields such as ocean fishing, rescue and disaster relief, and global search and rescue.

Benefit domestic services to the world

It is understood that the "Beidou" industrial chain is mainly concentrated in the user segment of the Beidou system, which is divided into three major links: upstream basic components, midstream terminals, and downstream operation services. Among them, the upstream basic components are mainly chips, boards, antennas and other basic components; midstream terminals mainly refer to navigation and positioning devices that can receive "Beidou" signals; downstream operation services mainly refer to government and enterprise users, industry users, Service providers and mass consumers provide various basic services such as positioning, navigation, timing, and short message communication based on "Beidou".

From providing services for the Asia-Pacific region to providing services for the world, Beidou's global networking not only means that Beidou has a wider service coverage, but also benefits the entire industry chain. Related industry chain products have an additional support system. These products The user experience, stability, and reliability of the device will be greatly improved, especially in the chip and terminal industries.

The efforts of Beidou's entire industrial chain benefit both domestically and globally. "In 2019, Beidou's overseas application cooperation and trade exchanges will become more frequent. Domestic Beidou basic products have been exported to more than 120 countries and regions. Based on Beidou's land right confirmation, precision agriculture, smart construction, smart ports, etc., it has been in ASEAN, South Asia, and Eastern Europe. , West Asia, Africa and other places have been successfully applied." Yu Xiancheng said.

Applications are only limited by imagination

The signal is on the horizon and applied around.

From clothing, food, housing, transportation to water, electricity, gas, and heat, from agriculture, forestry and fishery to disaster relief and mitigation... Beidou satellite navigation system is deeply integrated into social life and penetrates into all aspects of economic and social development.

Which way is smoother when driving on the road? How long does it take for the bus to arrive at the station for public transportation? How can I find a bike quickly when sharing a ride? No matter what mode of transportation you choose, you cannot do without the Beidou satellite navigation system.

The transportation industry is one of the largest users of Beidou satellite navigation systems. Beidou system is widely used in key transportation process monitoring, highway infrastructure safety monitoring, port high-precision real-time dispatch monitoring and other fields.

According to the "White Paper" data, as of the end of 2019, there were more than 6.5 million operating vehicles, 40,000 express and postal vehicles, about 80,000 buses in 36 cities, more than 3,200 inland navigation facilities, and more than 2,900 maritime navigation facilities in China. The Beidou system has been applied to the facilities, and the world's largest dynamic monitoring system for operating vehicles has been built.

When agriculture meets Beidou, planting is more labor-saving, seedling emergence is more worry-free, and labor productivity is greatly improved. In the farmland of Dashetai Town, Uradqian Banner, Bayannaoer City, Inner Mongolia Autonomous Region, unmanned planters are changing from "rare" to "common". Based on the Beidou positioning function, the planter operates on its own along a preset route. With this precise and scientific method, the seeding deviation per kilometer does not exceed 2 cm, and the seedling emergence rate per acre can increase by 10%.

When disaster warning meets Beidou, people are safer and property is guaranteed. Not long ago, in Leijiashan, Shimen County, Hunan Province, thanks to the "Beidou Satellite High-precision Earth Disaster Monitoring and Early Warning System", a timely warning was issued. Villagers located in the landslide-risk area were moved in time without any casualties. Through 24-hour real-time monitoring of the deformation and displacement of mountains, reservoirs, and rivers, Beidou provides early warning of possible landslides, subsidence, cracks, reservoir distress, and river water level surges to protect lives and reduce losses.

On the special battlefield, Beidou also responded quickly and played as sharply as possible. At the beginning of 2020, a battle against the new crown pneumonia epidemic was fought in the land of China. Vulcan Mountain and Leishen Mountain Hospitals rose on the ground. It was Beidou that achieved high-precision positioning and accurate mapping of complex terrain and landforms. The "location-finding" online drone platform can realize the precision spraying of drones and other epidemic prevention operations. It is also Beidou that provides high-precision data for it; material transportation vehicles are monitored and controlled in real time, and intelligent robots quickly send medical supplies from various places. The support system behind the hospital quarantine area is Beidou...

The Beidou system collides with new technologies such as 5G mobile communications, blockchain, Internet of Things, and artificial intelligence to build an emerging industrial ecological chain with Beidou space-time information as the main content, and promote changes in production and lifestyles and continuous innovation of business models. Create huge economic and social benefits.

In the future, Beidou has unlimited possibilities. Just as Academician Sun Jiadong, the first chief designer of the Beidou satellite navigation system, once said, “The application of Beidou is only limited by human imagination.”

  作为苹果 AirDrop 的竞争对手,谷歌也正在为运行 Google Play 服务的用户推送 Beta 版的 Nearby Share 功能,并且覆盖了 Android 和 Chrome OS 平台。近日有用户报告称,他们已经可以体验这项“附近文件分享”服务,但谷歌显然希望将之推广到更多的设备上。

android nearbyShare

  据悉,这项变化主要通过切换服务器端的开关来启用。感兴趣的朋友可前往通知栏,以检查是否有 Nearby Share 的图标出现。

  点击图标后,系统会询问用户是否需要打开 Nearby Share 功能。启用之后,即可检索附近的设备,以连接并分享选定的内容。

  此外 Nearby Share 提供了多个可见性选项,以限制对所有用户可见。

  值得一提的是,Nearby Share 也会根据启用状态而出现在分享列表中。自谷歌弃用 Android Beam 以来,这绝对是个让人感到欣喜的消息。

  有报道称,谷歌计划将该功能推广到所有运行 Android 6.0(Marshmallow)或更高版本的设备上。

  如果一切顺利,其有望于今年 8 月正式与广大 Google Play Services 用户见面,甚至推广到 Windows 和 macOS 设备平台。

解决方法如下:

不使用cordova.getActivity().startActivityForResult();这样调试跟踪后会发现被主Activity的OnActivityResult给拦截了。
解决方法使用 cordova.StartActivityForResult(cordovaplugin,Intent,int)

原因是:plugin会通过CordovaInterface中的startActivityForResult(cordovaPlugin,intent,int)方法启动该Activity。
当 Activity 结束后,系统将调用回调函数 onActivityResult(int requestCode, int resultCode, Intent intent)

  印度电子信息技术部日宣布,出于“安全”考虑,在印度市场禁止使用微信、TikTok (海外版抖音)、茄子快传、UC 浏览器、快手、美图等 59 款中国手机 App,引发轩然大波。

  据外媒最新报道,微信已经在印度下线,无法使用。
印度微信下线

  据大量印度用户反应,使用微信时会被强制退出,而且无法再登陆,并给出提示称:

  “依据印度法律,我们目前无法向您提供微信服务。我们尊重每一位用户,数据安全和隐私对我们而言是最重要的。我们正在与有关部门积极协调,希望能在未来恢复服务。”

  报道称,微信此番在印度下线,影响的都是使用印度本地手机号注册的用户,如果使用中国或其他非印度手机号注册,则仍然可以正常使用。

  有数据显示,2019 年,中印双方贸易总额高达 6395.2 亿元,其中中国对印度出口额为 5156.3 亿元,占两国贸易总额的三分之二。这意味着,中国的出口产品在印度市场具有较强的竞争优势。

  OpenJDK 项目正从 Mercurial 迁移到 GitHub,切换到 Git 源代码控制系统,预计迁移将在 2020 年 9 月完成。

  OpenJDK 从 2008 年起使用 Mercurial 管理源代码,如今部分 OpenJDK 项目如 Loom、Valhalla 和 JMC 已经迁移到 GitHub,还有部分项目正在迁移种,而到 9 月份 OpenJDK 主线也将正式加入进来。OpenJDK 是在 2018 年评估 Mercurial 的可能替代,其宗旨是提高新旧贡献者的生产力。

更多详情链接:https://www.infoq.com/news/2020/07/openjdk-github-migration/

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