1. ShotSpotter: listening in on the neighborhood
Total comment counts : 44
Summary
The article discusses the company formerly known as ShotSpotter, now called SoundThinking, and their outdoor acoustic gunfire detection system. The system involves installing acoustic sensors throughout a city to detect gunfire and determine its source. The company has been criticized for its secrecy in not disclosing the locations of its sensors and for attempting to suppress research into the civil rights impacts of its product. The article also mentions a leaked spreadsheet of SoundThinking sensors and discusses the author’s expedition to find and observe the sensors. It highlights concerns about the possibility of conversations being recorded by the sensors and used as evidence in criminal trials, as well as the larger issue of pervasive surveillance in urban areas. The density of SoundThinking sensors in Albuquerque, where the author conducted their expedition, is also discussed.
Top 1 Comment Summary
The article discusses the contentious issue of policing in Albuquerque, specifically focusing on the use of surveillance technology and the controversial ShotSpotter program. The police department’s lack of transparency and accountability has been a major concern, while understaffing is also an issue. The article mentions the extensive surveillance capabilities of the police department, including access to thousands of cameras and the use of facial recognition technology. The author highlights the frustration over APD’s refusal to disclose which areas are covered by ShotSpotter. The controversy surrounding ShotSpotter revolves around its effectiveness and whether it is worth the city’s investment.
Top 2 Comment Summary
The article discusses how the distance between a person’s house and a ShotSpotter sensor is correlated with their household income. It suggests that wealthier individuals tend to have less surveillance. The author mentions that this pattern could also be due to more gun crime leading to increased surveillance. However, it is unclear whether knowing the location of the sensors is advantageous for offenders when the sensors are densely placed.
2. CS 6120: Advanced Compilers: The Self-Guided Online Course
Total comment counts : 16
Summary
CS 6120 is a PhD-level course at Cornell University on programming language implementation. It covers topics such as intermediate representations, data flow, optimizations, parallelization, just-in-time compilation, and garbage collection. The course involves reading papers and completing open-source hacking tasks using LLVM and an educational IR. The curriculum includes lessons with videos, written notes, and implementation tasks. The course project involves changing the world through compilers. The course is open source and available on GitHub.
Top 1 Comment Summary
The author believes that understanding computer architectures and the generation of efficient machine code is important before writing compilers. They express concern that computer architecture and systems programming are being de-prioritized in schools and universities, possibly because they are seen as too technical. However, the author believes that this knowledge is essential for securing top jobs in the industry.
Top 2 Comment Summary
The author credits a particular course for helping them secure interviews and clear the hiring process at several prominent tech companies. The course complemented the author’s university curriculum in low-level computing systems and their open source contributions by providing valuable knowledge for answering difficult interview questions.
3. Algorithmic Thinking (2nd Edition)
Total comment counts : 4
Summary
The article is a promotion for the book “Algorithmic Thinking: Unlock Your Programming Potential” by Dr. Daniel Zingaro. The book provides a comprehensive guide to data structures and algorithms, including topics such as hash tables, recursion, dynamic programming, trees, graphs, and heaps. The content includes real-world examples from programming competitions and practice exercises to prepare readers for coding interviews. The code examples are written in C but can be applied to other programming languages. The author, Dr. Daniel Zingaro, is an award-winning professor and author in the field of active learning and coding education. The article includes reviews praising the book’s clarity, practicality, and comprehensive coverage of algorithms.
Top 1 Comment Summary
The user is asking for a comparison between two books: “Introduction to the Theory of Computation” and “Algorithm Design Manual” by Skiena.
4. Generating transparent images using Stable Diffusion XL
Total comment counts : 5
Summary
This article discusses an extension for SD WebUI that generates transparent images and layers. The extension is currently a work in progress and may change significantly in the future. The article also provides instructions and models for testing the transparent image generating functionality. The author encourages users to go through a sanity check to ensure accurate results. The article concludes with a test using the extension on an anime model.
Top 1 Comment Summary
The author is reviewing an image of a woman with messy hair and high quality. They notice that the hair farther from her head looks incorrect, similar to how iPhone portrait mode can sometimes make hair appear messy. The author speculates that this could be an instance of an AI being trained on partially AI-generated data and reproducing these flaws.
Top 2 Comment Summary
The article discusses the impressive feature of partial alpha blending support for translucent materials like glass and plastic. The author expresses curiosity about how well this feature would work with inpainting, and mentions that img2img is also on the author’s to-do list.
5. Ask HN: How can I learn about performance optimization?
Total comment counts : 66
Summary
This article provides several tips for optimizing code performance.
First, it emphasizes the importance of measuring performance regularly to identify areas that need improvement.
Next, it suggests that making code go faster can often be achieved by doing less work. This can be accomplished through using more efficient algorithms, refactoring code to eliminate unnecessary operations, and moving repeated work outside of loops.
Understanding the performance characteristics of the system is also crucial. Knowing whether the application is CPU bound, GPU compute bound, or memory bound helps in identifying bottlenecks and optimizing accordingly.
The article also suggests considering solving a different problem as a way to optimize code. Sometimes, there are easier and equivalent problems that can be solved instead, avoiding unnecessary complexity. This is commonly seen in graphics programming.
Top 1 Comment Summary
The article provides helpful tips for optimizing performance in the context of video games. The author emphasizes the importance of measuring performance regularly to identify areas for improvement. They suggest using more efficient algorithms, eliminating unnecessary operations, and moving repeated work outside of loops to make things faster. It is also crucial to understand the performance characteristics of the system, whether it is CPU bound, GPU compute bound, or memory bound. Additionally, the author suggests solving a different problem if possible, as there may be easier and equivalent alternatives that can achieve the desired outcome.
Top 2 Comment Summary
The article is written by a former High-Frequency Trading (HFT) developer and focuses on performance issues in software development. The author suggests that the main sources of performance problems are CPU cycles being consumed by certain operations and efficiency in memory usage. The author mentions that operations such as iterations and string operations can consume CPU cycles, while lock contentions in multi-threaded environments and wait states can waste CPU resources. The article also highlights that understanding these principles is essential and that techniques may vary depending on the platform or version being used. The author gives examples from the past where certain techniques were commonly used, but they may no longer be necessary due to advancements in technology. Overall, the article emphasizes the importance of understanding performance issues and adapting techniques accordingly.
6. The One Billion Row Challenge in Go: from 1m45s to 4s in nine solutions
Total comment counts : 32
Summary
The article discusses the author’s exploration of the One Billion Row Challenge using the Go programming language. The challenge involves processing a large text file containing weather station names and temperatures and calculating the minimum, mean, and maximum temperatures for each station. The author develops nine solutions in Go, each faster than the previous, with the final solution running in about 4 seconds. The author shares their approach, highlights the use of Go’s profiler to identify performance bottlenecks, and compares their solutions to others in the Go community. The article also includes benchmark measurements and code snippets to illustrate the optimizations made. The author emphasizes using only the standard library and achieving a processing speed comparable to a heavily optimized Java solution.
Top 1 Comment Summary
The article discusses the importance of optimizing code when working with large datasets. The author states that they have never had to consider this issue before, as their previous data was small enough to not require optimization. They found the section about baseline measurements with simple commands like cat and wc to be particularly interesting, as it provides a perspective on what is considered “reasonable” performance.
Top 2 Comment Summary
The article discusses the author’s curiosity about how long it would take to complete a task using Polars for scale. They mention that it took approximately 33 seconds. The author then expresses their interest in finding the simplest solution using a well-known library or database that can achieve similar performance to a hand-optimized solution.
7. Under the Microscope: Three Dirty Dwarves
Total comment counts : 2
Summary
The article discusses a hidden cheat code and development features in the game “Three Dirty Dwarves.” The cheat code, known as MOSHOLU, enables cheat mode and allows players to select their starting level. The article reveals the presence of other hidden passwords, such as SUPERHERO and JOYRECORD, and explains their functions. The passwords were found to be encoded and scrambled, but through reverse engineering and analyzing the game’s source code, the article manages to decipher the scrambling algorithm. Furthermore, it is revealed that the passwords in the game are named after locations in the Bronx, New York. The article concludes by mentioning that the purposes of some passwords remain unknown, unless the game makers provide further information.
Top 1 Comment Summary
The article discusses the hidden features and possibilities in Sega Saturn games. It mentions that the Saturn has good tools for reverse engineering, including a save state loader for Ghidra and the Mednafen debugger, which allows for editing memory in real-time. The author also discovered a long-held secret cheat code for Clockwork Knight 2 that provides access to the entire first game.
Top 2 Comment Summary
The article discusses the concept of creating a cheat code system that is resistant to decompiling and examinations. The author suggests utilizing a code that is interpreted as a memory address or jump, where most actions do nothing or lead to crashes.
8. Zoomable, translated version of the 15th century Mappa Mundi
Total comment counts : 11
Summary
The article simply states that by continuing to browse a certain website, the user is agreeing to the website’s use of cookies and encourages them to learn more about it.
Top 1 Comment Summary
The author had a list of “must-sees” when they went to Venice, one of which was the Fra Mauro original map. They were disappointed to find out that the map was removed for restoration and they were unable to see it. The author learned a lesson and now calls places ahead of time to confirm their hours and current offerings.
Top 2 Comment Summary
The article discusses a famous error found on old maps called mappa mundi, which is the depiction of California as an island. It refers to a Wikipedia page that provides more information about this topic.
9. David Holladay, blindness technology pioneer, has died
Total comment counts : 1
Summary
David Holladay, an influential figure in the world of braille software, has passed away following an accident at home. He was a pioneer in developing accessibility for blind users through his work on Apple II computers in the 1980s. David and his wife, Caryn Navy, founded Raised Dot Computing, later known as Braille Planet. They joined Duxbury Systems in 1999, where David focused on expanding the reach of DBT, a software for translating text into braille, to numerous countries and languages. Despite being bedridden in recent years, David’s passion for braille never waned, and he continued working until his last day. His funeral will be held in Massachusetts, and streaming of the service will be available online. The braille community mourns the loss of David and his contributions to the field.
Top 1 Comment Summary
The article discusses the passing of the author’s father, who developed braille translation software. The software, such as BRAILLE-EDIT, MegaDots, and DBT, along with accessibility tools in popular smartphones, helped facilitate braille-to-print and print-to-braille translations in multiple languages. The author invites those interested in the history of braille translation technology to explore the archive of the Raised Dot Computing Newsletter, which was written by the father and his wife in the 80s and 90s.
10. An Unbelievable Demo (2021)
Total comment counts : 8
Summary
The article tells the story of the author’s encounter with a Sun Microsystems employee who claimed to be a DTrace expert. The author expected an impressive demonstration of the company’s new DTrace-based product but was underwhelmed when the employee showed basic functionality that was already available in the GUI. The author, who had developed his own DTrace tools, felt that the employee didn’t appreciate the value of his work. The article highlights the author’s disappointment with the lack of innovation in the company’s product demo.
Top 1 Comment Summary
The article discusses the belief at Sun that only the company itself could effectively use its own technologies, and anything created outside of Sun was considered inferior. This mindset was evident during the OpenSolaris era, where criticism of Sun’s open source strategy was met with disbelief and a sense of reverence for the company.
Top 2 Comment Summary
This article discusses the author’s discovery that Sun Microsystems was selling their open source tools without their permission. The author shares their experience and discusses the implications of this unauthorized selling.