• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 1997.03a
• /
• pp.1-17
• /
• 1997

소프트웨어 시스템 개발의 수명 주기에서 유지 보수 단계에 투입되는 시간과 비용은 상당한 비율에 달한다. 그 결과, 과거에는 시스템을 개발할 때 , 프로그래밍에 중점을 두었지만 현재는 유지 보수에 중점을 두고 있는 실정이다. 따라서,효과적인 소프트웨어의 창출을 위해서는 좀더 나은 유지보수기법을 도출할 필요가 있다. 또한 소프트웨어의 중요성을 감안할 때 특히 소프트웨어에 대한 성능이 추가, 수정 , 보완을 원활하게 할 수 있는 소프트웨어 유지보수 기법의 적용이 절실하다 하겠다. 본 연구에서 측정요인(프로그램 크기, 복잡성, 구조적 개발방법론)에 따라서 어떠한 유지보수기법의 효과적인가를 실험을 통하여 도출해보았다.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.2
• /
• pp.86-94
• /
• 2007

The NoC (network-on-chip) approach is a promising solution to the increasing complexity of on-chip communication problems because of its high scalability. But, NoC applications generally consume a lot of power, because they require a large design space to accommodate many parallel IPs and network communication channels. It is not easy to analyze the power consumption of NoC applications with conventional simulation methods using simple power models. In addition, there are also many limitations in using sophisticated simulation models because they require long execution time and large efforts. In this paper, we apply a cycle-accurate energy measurement technique and tool to the FPGA prototypes, which are generally used to verify the correctness of SoC designs, as a practical indication of the power consumption of real NoC applications. An NoC-based JPEG encoder implementation is used as a case study to demonstrate the effectiveness of our approach.

• Journal of Advanced Navigation Technology
• /
• v.22 no.4
• /
• pp.325-335
• /
• 2018

Limited access to state information in the design of a feedback controller has brought out a significant amount of research on the design of an output feedback controller. Despite its long endeavor to find an optimal one, it is still an open problem. Thus, we focus on the comparison of existing states of arts in the design of a static output feedback controller in terms of stability and complexity so as to find further research direction in this field. To this end, we present eight design methods in a unified presentation. We also provide the complete description of algorithms which can be applicable to any system configuration. Stability performance and complexity in terms of processing time are evaluated through numerical simulations. Simulation results show that the algebraic controller (AC) algorithm [20] has the smallest complexity while the scaling linear matrix inequality (SLMI) algorithm [18] seems to achieve the best stability in most cases with much higher complexity.

• The Journal of the Korea Contents Association
• /
• v.21 no.4
• /
• pp.67-76
• /
• 2021

Three research hypotheses expected when working with a mobile app were verified. As follows: (1) Usability varies depending on the external structure of the tree-view menu. (2) If the menu arrangement is different from the script expected by users, the usability is poor. And (3) the effects of each of these two hypotheses vary depending on the complexity of the task. To this end, a script for booking accommodations expected by undergraduate students was written, and an experiment was designed with the task completion time and error rate as dependent variables. The experiment was conducted by implementing a prototype for reservation system on a smartphone As a result, while the overall performance was unfavorable when the task was complicated, the superiority of sectional menu was prominent when the task was complicated, and positive responses were observed when the menu arrangement in a complicated task matched user expectations. By discussing these results, it was found that when designing a procedural menu on a mobile screen, we come up with measures to minimize the burden of working memory, consider what tree-views are for the task, and that in complex tasks, menus should be arranged according to the scripts expected by users.

• Journal of the Economic Geographical Society of Korea
• /
• v.18 no.4
• /
• pp.539-555
• /
• 2015

This study proposes the methodology for measuring the time-distance accessibility on the Seoul bus system based on the T-card transaction databases and analyzes the results. T-card transaction databases contain the time/space information of each passenger's locations and times of the departure, transfers, and destination. We introduce the bus network graph and develop the algorithms for time-distance accessibility measurement. We account the average speed based on each passenger's get-in and getoff information in the T-card data as well as the average transfer time from the trip chain transactions. Employing the modified Floyd APSP algorithm, the shortest time distance between each pair of bus stops has been accounted. The graph-theoretic nodal accessibility has been given by the sum of the inverse time distance to all other nodes on the network. The results and spatial patterns are analyzed. This study is the first attempt to measure the time-distance accessibility for such a large transport network as the Seoul bus system consists of 34,934 bus stops on the 600 bus routes, and each bus route can have different properties in terms of speed limit, number of lanes, and traffic signal systems, and thus has great significance in the accessibility measurement studies.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.1
• /
• pp.80-88
• /
• 2001

The existed approaches to analyzing real-time schedulability take place exponential time and space complexity of this methods, since these uses a fixed priority scheduling and/or traverse all possible state spaces. This paper judges whether it is satisfied a given deadlines for real-time processes regarding a minimum execution time of process, periodic, deadline and a synchronizion time of processes by using the transaction rules of process algebra, and proposes a retrieval algorithm for unschedulable processes based on GUI environment. And we implement and evaluate the scheduling state analyzer that displays visually the result of schedulabiliy analysis for real-time processes.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.12
• /
• pp.28-33
• /
• 2007

We present a space-time trellis coded OFDM system in flow fading channels. Generalized principal ratio combining (GPRC) is also analyzed theoretically in frequency domain. The analysis show that the decoding metric of GPRC include the metrics of maximum likelihood (ML) and PRC. The computer simulations with M-PSK modulation are obtained in frequency flat and frequency selective lading channels. The decoding complexity and simulation running times are also evaluated among the decoding schemes.

• Proceedings of the Korean Information Science Society Conference
• /
• 1999.10b
• /
• pp.506-508
• /
• 1999

본 논문에서 제안하는 계층적인 형태의 deformable model을 이용하면 기존의 deformable model 방법이 가지고 있던 여러 문제점을 해결할 수 있다. 특히 가장 큰 문제중의 하나인 초기위치를 찾는 문제나 적용시간이 오래 걸린다는 단점을 상당부분 해결할 수 있다. 또한 계층적인 형태를 사용하면 최종적으로 찾고자 하는 문체가 증가될수록 더 많은 시간상/공간상의 이익을 볼 수 있게 된다. 본 논문에서는 이처럼 계층적인 형태로 deformable model을 구성하는 방법과 계층적 deformable model을 영상에 적용하는 방법, 그리고 그 방법에 대한 공간적/시간적 복잡도 분석을 통해 그 효율성을 알아보았다.

• Journal of Korean Society of Transportation
• /
• v.22 no.5
• /
• pp.61-73
• /
• 2004

The efficiency of the real-time route guidance system(RGS) depends largely on the quality of route search algorithms. In this paper, we implement the coarse grid method(CGM) in mathematical programming for finding a good quality route of real-time RGS in large-scale networks. The proposed CGM examines coarser and wider networks as the search phase proceeds, in stead of searching the whole network at once. Naturally, we can significantly reduce computational efforts in terms of search time and memory requirement. We demonstrate the practical effectiveness of the proposed CGM with nationwide real road network simulation.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.34 no.s01
• /
• pp.48-54
• /
• 1989

An immunoassay techniques using monoclonal antibodies have been developed of the quantitative analysis of endogenous hormones in plants. In order to be useful for immunoassay, both a high degree of specificity and a high affinity are required. A system is described for production of hybridomas which secrete antibodies against the plant hormone. Using the system we were able to produce hybridmas with the desired antibody specificity by cell fusion and culture method. For a number of obvious reasons, monoclonal antibodies(mAb) were superior to polyclonal antibodies.