홍성수 교수

We propose a technique for analyzing cache-related preemption delays of tasks that cause unpredictable variation in task execution time in the context of fixed-priority preemptive scheduling. The proposed technique consists of two steps. The first step performs a per-task analysis to estimate cache-related preemption cost for each execution point in a given task. The second step computes the worst case response time of each task that includes the cache-related preemption delay using a response t

The paper presents a comprehensive design methodology for guaranteeing end to end requirements of real time systems. Applications are structured as a set of process components connected by asynchronous channels, in which the end points are the system's external inputs and outputs. Timing constraints are then postulated between these inputs and outputs; they express properties such as end to end propagation delay, temporal input sampling correlation, and allowable separation times between updated

We describe our experiments on a real-time system design, focusing on design alternatives such as scheduling jitter, sensor-to-output latency, intertask communication schemes and the system utilization. The prime objective of these experiments was to evaluate a real-time design produced using the period calibration method (Gerber et al., 1995) and thus identify the limitations of the method. We chose a computerized numerical control (CNC) machine as our target real-time system and built a realis

We present a programming language with first-class timing constructs, whose semantics is based on time-constrained relationships between observable events. Since a system specification postulates timing relationships between events, realizing the specification in a program becomes a more straightforward process.Using these constraints, as well as those imposed by data and control flow properties, our objective is to transform the code so that its worst-case execution time is consistent with its

Summary Android smartphones are often reported to suffer from sluggish user interactions due to poor interactivity. This is partly because Android and its task scheduler, the completely fair scheduler (CFS), may incur perceptibly long response time to user‐interactive tasks. Particularly, the Android framework cannot systemically favor user‐interactive tasks over other background tasks since it does not distinguish between them. Furthermore, user‐interactive tasks can suffer from high dispatch l

Because of the technology convergence in computer, consumer electronics, and communication fields in the last decade, embedded computing has rapidly emerged as an important computing discipline. Currently, demands from a variety of embedded systems applications are continuously increasing and the interest in embedded computing technologies is growing very rapidly all over the world. Thus, embedded computing deserves separate and dedicated journals that can accommodate the many original technolog

We present a programming language with first-class timing constructs, whose semantics is based on time-constrained relationships between observable events. Since a system specification postulates timing relationships between events, realizing the specification in a program becomes a more straightforward process. Using these constraints, as well as those imposed by data and control flow properties, our objective is to transform the code so that its worst-case execution time is consistent with its

This paper presents a compiler-based approach to tuning real-time programs under fixed priority scheduling. It has two interrelated components, a static code transformation algorithm and a modified rate-monotonic scheduling method. The code transformation tool decomposes an unschedulable task into two subtasks, one that is time critical and the other that is unobservable. This is made possible by an event-based semantics in that a program's external behavior is determined soly by externally obse

The software components of embedded control systems get extremely complex as they are designed into distributed sys- tems consisting of a large number of inexpensive microcontrollers interconnected by low-bandwidth real-time networks such as the controller area network (CAN). While recently emerging middleware technologies such as CORBA and DCOM address the com- plexity of distributed programming, they cannot be directly applied to distributed control system design due to their excessive re- sou

A colorimetric loop-mediated isothermal amplification assay detects changes in pH during amplification based on color changes at a constant temperature. Currently, various studies have focused on developing and assessing molecular point-of-care testing instruments. In this study, we evaluated amplified DNA concentrations measured using the colorimetric LAMP assay of the 1POT™ Professional device (1drop Inc, Korea). Results of the 1POT analysis of clinical samples were compared with measurements

SDR 기술의 산업적 가능성이 가시화되면서 SDR 시스템의 실제적인 소프트웨어 표준인 SCA의 중요성이 급격히 부각되고 있다. SCA는 다양한 통신 waveform 을 처리하는 응용 소프트웨어 컴포넌트들이 설치, 수행, 제거되는 환경을 제공하여, SDR 시스템이 다중 모드로 동작될 수 있도록 만들어 주는 핵심 소프트웨어 계층이다. 본 논문에서는 이런 다중 모드 SDR을 지원하는SCA 기반 waveform 소프트웨어의 구조를 설명하고, 이들의 QoS를 보장할 수 있는 추가적인 메커니즘을 제안한다. 구체적으로 우리는 waveform 소프트웨어의 QoS 속성을 기술할 수 있도록 기존 SCA의 도메인 프로파일을 확장한다. 이어서 이렇게 기술된 QoS를 보장하기 위해 SCA에 새로이 Admission Controller와 Resource Allocator 모듈들을 추가하고, SCA의 waveform 소프트웨어가 생성되어 초기화 과정을 수정하여 제안한다. 한편 SCA에는 QoS 보장 이외에도