English

The Common Spatial Data Infrastructure (CSDI) is a key initiative under the Smart City Blueprint for Hong Kong. The CSDI portal launched by the Development Bureau (DEVB) provides a map-based digital infrastructure as a one-stop platform to open and share spatial data. By allowing members of the public to search, view and download various kinds of spatial data from the portal, a wide range of possibilities for application development will be opened, the digital economy boosted and quality of life improved.

In 2022, I launched a Kotlin podcast show, Kotlin Fireside Chat, with my friends in Kotlin User Group. Now, we're taking things to the next level by building a podcast website with a statistical analysis dashboard. We've built a static website using Jamstack and connected it to a serverless API written in Kotlin. In order to aggregate the listener number across platforms, such as YouTube, BiliBili, Ximalaya, Lizhi, Qingting, we've also created a crawler to grab those numbers and display them in a custom dashboard.

The Domain Name System (DNS) has changed dramatically over the last decade. There are now more than 1,200 active generic Top-Level Domains (gTLDs) representing many different scripts and character strings of varying length (e.g., .дети, .london, .engineering). There are also more than 60 Internationalized Domain Names (IDNs) country code top-level domains (ccTLDs) representing global communities online in native scripts (e.g., .ไทย).

I want to talk about some interesting cases and tips that I met when using Postgres in my daily job, which are topics general enough that most developer may also meet in their daily jobs (even for non-Postgres developers).

• Why LIMIT 1 is MUCH SLOWER than LIMIT 100?
• What's wrong with JSONB? (hint: it's TOO robust)
• Efficient query using LATERAL subquery (from 8s to 0.08s)

In HKOSCon 2022, we discussed how Home Assistant could help to bridge the gaps between smart home products from different camps with local control in mind. We touch-based on the emerging yet promising Matter standard that hoped to resolve a lot of the interpretability challenges of different smart home ecosystems. One year on, products that comply with the Matter standard start to appear, and Home Assistant has also evolved to provide better support for Matter products.

Raspberry Pi already know well and many of you now using for your DIY hobbies and business. Do you are having fun playing with it/Is Raspberry Pi useful for your business? Masafumi will give a talk with a couple of use cases, demonstrate some of Raspberry Pi DIY gadgets and discuss what the use case is good to apply your DIY hobby/business projects.

This project demonstrates that multiple robots can collaborate to explore an unknown environment without GPS to generate a map with reasonable accuracy. This addresses exploration as a problem in the planning layer of the robotics domain. A frontier-based  exploration methodology will be explained. The main approach uses Rapidly-expanding Random Trees for frontier detection, and map merging for information sharing. The developed algorithm also makes use of existing solutions for SLAM, and path planning. The algorithm runs in a network of robots, and a master machine on ROS.

Unikernels are specialized operating system images that execute a single application. Through extreme specialization they can provide high performance, small memory footprints, fast boot times, and a reduced attack vector.

This talk will provide an overview of Unikraft (https://unikraft.org), a Linux Foundation project that provides a toolikit for creating highly specialized unikernels by combining a set of micro-libraries to tailor down the operating system strictly to the needs of the executing application.

Many aspiring businesses in various industries need to make use of software as they grow. Open source software development workflows generally allows businesses to keep costs low, are scalable and are also proven to work across different locations, cultures and timezones. In this talk, Gary aims to share the importance of having a good software coding foundation for your business, especially if the business is not purely software-focused. He will share essential parts of a coding foundation that even the tech giants use, thus you can be rest assured of their proven scalability.