• Korean Journal of Cognitive Science
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• v.24 no.1
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• pp.71-93
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• 2013

Multitasking has become part of our life. Self-interruption and switching to another task become easier and more frequent. According to previous studies, however, most of the task-switching incurs a cognitive cost. This study investigated the benefit from task switching. In Study 1, participants performed two tasks were similar, and negative correlation between the number of task switching and performance were confirmed, this result is similar to previous studies. Study 2 has shown that, made a comparison of two conditions, between possible and impossible conditions in terms of task switching. Depending on switching preference, the result of task performance has differentiated and the emotion that participants had before the task has changed. Depending on participants' switching preference, there were different amount of switching cost. Moreover, for participants who preferred task switching highly than others, task switching occurred more benefit than cost.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.5_6
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• pp.335-346
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• 2004

PtolemyII is an environment that supports heterogeneous modeling and design of concurrent systems such as embedded system. PtolemyII has several Domains which are physical rules to determine the way of communicating between components. PtolemyII has 11 domains such as PetriNet, Timed Multitasking, SR etc. Components of System can be specified using appropriate domains for their properties. Communicating Sequential Processes(CSP) is implemented as formally designed CSP domain, in PtolemyII. But CCS didn't be implemented as a domain. It is a kind of Process Algebra language which can be used for specifying and verifying concurrent systems formally. Thus, in this paper we implemented CCS domain. And that permitted developers using PtolemyII to use the same modeling pattern used in PtolemyII and to make system specifications in the base of the formal semantics of CCS. This caused the diversity of PtolemyII domains and the power of expression was improved. This paper will explain the structure of CCS domain implemented in PtolemyII and the way of implementing it.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.139-143
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• 2018

Arduino, based on open source hardware, is used in many IoT devices, and IoT devices require multitasking for various inputs and outputs. Among the several methods used for multitasking based on Arduino, we compare three methods: Timing Call by using millis(), Simple Timer library method, and Timer library method. In order to measure the execution error caused by measurement and time delay of each method, two situations are created and analyzed. In the first case, 10 random tasks of a certain size are generated to measure the time delay of each method. In the second situation, 10 random tasks of a certain size are generated to compare execution errors caused by the time lag of the Timer library. In the first case, the millis() timing call method and the Simple Timer library method have a similar time delay and the Timer library method has more time delay. In the second situation, an execution error occurred in which small-size tasks were not called back at the correct timing due to the time delay.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.5
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• pp.49-54
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• 2022

With the recent widespread adoption of general-purpose GPUs (GPGPUs) in cloud systems, maximizing the resource utilization through multitasking in GPGPU has become an important issue. In this article, we show that resource allocation based on the workload classification of computing-bound and memory-bound is not sufficient with respect to resource utilization, and present a new thread block scheduling policy for GPGPU that makes use of fine-grained resource utilizations of each workload. Unlike previous approaches, the proposed policy reduces scheduling overhead by separating profiling and scheduling, and maximizes resource utilizations by co-locating workloads with different bottleneck resources. Through simulations under various virtual machine scenarios, we show that the proposed policy improves the GPGPU throughput by 130.6% on average and up to 161.4%.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.2
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• pp.103-109
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• 2013

Traditional implementation schemes for automotive electronic control units look simple, but the tradition schemes need so many coarse works to satisfy the user requirements regarding time constraints whenever their microprocessors are changed. Recently, a movement toward using middle-wares, such as OSEK operating system, has risen in automotive industry. In this paper, we describe how to use the features of operating systems to replace traditional firmware based softwares in points of views of services, such as multitask support, preemption, and realtime property. To show an example, we implemented a parking assistance system as a prototype.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.762-766
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• 2004

This paper introduces a testbed which is suitable for the study of security issues arising in applications involving internet appliances. The testbed implements secure door locks by utilizing the intranet in the building and is composed of two main parts, namely a database server and door locks each of which equipped with a custom-made embedded system. The main objective is to provide a platform for teaching the conflict among real-time specifications, security requirements, and limited-resource constraints. After definitions of threat, vulnerability, and attack are given, we discuss how the testbed can be applied as an education tool for these concepts. Finally, the effects of sequential and multitasking operations are given as a case study.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1181-1184
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• 2005

In this paper, we proposed small scale real-time operating system for embedded system. Real-time system is characterized by the severe consequences that result if logical as well as timing correctness properties of system are not met. On real-time system, real-time operating system allows real-time applications to be designed and expanded easily. Functions can be added without requiring major changes to the software. We design small scale real-time operating system for preemptive kernel, and design kernel component such as multitasking, scheduler, task priority, semaphore, inter-task communication, clock tick timer, ISR(Interrupt Service Routine) mechanism has low interrupt latency.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.3
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• pp.14-23
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• 1994

A natural language processing system usually has the demerit that its processing time is relatively long. If an interactive system makes its user kept waiting long, it can't be said to be practical. In this paper, the on-line natural language parser in which its processing coincides with the sentence's inputting is designed. Since the greater part of morpholgical and syntatic semantic analysis is already performed during the keyboard input, user can get a prompt response. Moreover, the Korean parser is implemented in multitasking environment, and it is compared with an off-line parser. The on-line parser can be considered to be efficient for its real time processing.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.91-93
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• 2002

본 논문은 RISC CPU인 Intel StrongARM SA-1100을 기반으로 하는 실시간(Real-Time) 운영체제를 설계한 내용을 설명하고 있다. 본 논문에서 구현된 운영체제는 태스크들이 우선순위 기반으로 저리되는 선점형 스케줄링 방식을 채택함으로써 실기간 운영체제의 주요 특징인 시간 결정성(determinism)을 보장하도록 하였다. Intel StrongARM SA-1100은 고성능(High Performance), 저전력(Low Power)의 장점 때문에 모바일(Mobil) 환경에서 많이 사용되고 있다. 본 논문은 Intel StrongARM SA-1100 CPU를 타겟으로 시간 결정성이 보장되도록 멀티 태스킹(Multitasking)과 ITC(InterTasking Communication)를 설계하고 구현한 내용에 대해 설명하고 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.58-60
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• 2002

실시간 운영 체제(Real-Time Operating System)는 특정 태스크가 정해진 시간 안에 수행될 수 있도록 시간 결정성(Determinism)을 보장하는 운영 체제이다. 실시간 운영테제는 멀티태스킹(Multitasking) 및 ITC(InterTask Communication 혹은 IPC, Interprocess Communication)을 제공한다는 점에서는 일반 운영체제인 Unix$^{TM}$, Linux$^{TM}$, Windows$^{TM}$ 등과 같지만, 시간 결정성을 보장한다는 점에서 일반 운영 체제와 다르다. 또만 실시간 운영 체제를 포함한 임베디드 시스템(Embedded System)은 일반적으로 디지털 카메라, 디지털 TV, DVD 등에서 수행되므로 실행 이미지(Image) 크기가 작아야 한다. 본 논문에서는 실시간 운영체제의 실행 이미지를 줄이면서 시간 결정성을 보장한 수 있도록 메모리 관리 체계를 설계하고 구현한 내용을 설명한다.