Lock-free atom garbage collection for multithreaded Prolog

The runtime system of dynamic languages such as Prolog or Lisp and their derivatives contain asymbol table, in Prolog often called theatom table. A simple dynamically resizing hash-table used to be an adequate way to implement this table. As Prolog becomes fashionable for 24 × 7 server processes we need to deal with atom garbage collection and concurrent access to the atom table. Classical lock-based implementations to ensure consistency of the atom table scale poorly and a stop-the-world approach to implement atom garbage collection quickly becomes a bottle-neck, making Prolog unsuitable for soft real-time applications. In this article we describe a novel implementation for the atom table using lock-free techniques where the atom-table remains accessible even during atom garbage collection. Relying only on CAS (Compare And Swap) and not on external libraries, the implementation is straightforward and portable.

The Study on the Innovation Bicycle Design Using Functional Element Characteristics

The design method on bicycle’s functional elements proposed by this research is based on analysis on the winning work in the Global Bicycle Design Competition. Via analyzing its creative design on functional elements, our study is aimed to establish a creative design method on bicycle for designers to develop lots of creative ideas at the concept development stage. This research is divided into three stages, including analysis on bicycle’s creative design elements, construction of creative design method flow on bicycle’s functional elements, and case study on design prototype. For analysis on bicycle’s creative design elements, we have come up with a symbol table of bicycle’s creative functional elements (CFEs). As to construction of creative design method flow on bicycle’s functional elements, we first asked the designer to describe his/her design theme, and then picked bicycle’s CFEs according to the contents described. After CFEs were picked, we then conducted the space position arrangement of functional element symbols. Based on designer’s requirements, we produced several kinds of space arrangements on CFEs, and then we designed a new bicycle by referring to the symbol table of bicycle’s CFEs acquired. In the final step, we followed the flowchart of bicycle’s CFEs constructed by this research, and proceeded a case study prototype design.

Digital Hardware Design Formal Verification Based on HOL System

This article selects HOL theorem proving systems for hardware Trojan detection and gives the symbol and meaning of theorem proving systems, and then introduces the symbol table, item and the meaning of HOL theorem proving systems. In order to solve the theorem proving the application of the system in hardware Trojan detection requirements, this article analyses basic hardware Trojan detection methods which applies for theorem proving systems and introduces the implementation methods and process of theorem proving about hardware Trojan detection.