• 한국통신학회논문지
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• 제31권5A호
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• pp.469-474
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• 2006

본 논문에서는 High Speed Data Packet Access(HSDPA) 시스템의 평균 sector throughput 분석 방법을 개발하였다. 제안하는 성능 분석 방법은 Adaptive Modulation and Coding(AMC)와 scheduling 기법, multi-code 전송의 영향을 반영할 수 있으며, link budget을 응용한 간단한 계산 과정들을 통해, HSDPA의 성능을 분석할 수 있다. 일반적으로, link budget은 셀 coverage를 산출하는 목적으로 사용되었으나, 본 논문에서는 AMC가 적용되는 CDMA 시스템 환경에서 특정 위치에 있는 사용자의 C/I를 계산할 수 있도록 변형하였다. 또한, 개발된 분석 방법을 활용하여, scheduling 기법과 multi-code 전송이 HSDPA 시스템 성능에 미치는 영향을 분석하였다.

• Journal of the Optical Society of Korea
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• 제19권5호
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• pp.514-520
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• 2015

This paper presents a novel shore-to-sea maritime data transmission system based on time-code diversity, using visible light in maritime environments to overcome the limitations of conventional maritime wireless communications. The proposed system is primarily comprised of existing LED-based lighthouses and maritime transceivers (marine beacons, buoys, etc.), and thus is considered cost-effective in terms of implementation. We first analyze maritime visible-light communications on the basis of the unique properties of a maritime environment, i.e. sea states (wave height, wind speed, etc.), plus atmospheric turbulence, using the Pierson-Moskowitz (PM) and JONSWAP (JS) spectrum models. It is found that the JS model outperforms the PM model, and that the coverage distance depends on the LED power and sea states. To combat maritime fading conditions that significantly degrade performance and coverage distance, we propose a time-code diversity (TCD) scheme in which the delayed versions of the original data are retransmitted using orthogonal Walsh codes. This TCD scheme is found to be superior, in that it offers three orders of magnitude in terms of BER performance, compared to a conventional (non-TCD) transmission scheme. The proposed scheme is robust and efficient in overcoming the effect of impairments present in maritime environments with a BER of approximately $10^{-5}$and a data rate of 100 Kbps at a distance of 1 km.

• 척추신경추나의학회지
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• 제18권2호
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• pp.53-64
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• 2023

Objectives This study aimed to investigate the status of Chuna manual therapy(CMT) usage before and after COVID-19 social distancing measures. Methods This study utilized Health Insurance data from April 2019 to May 2023. Quarterly data were collected for Simple Chuna (code 40710), Complex Chuna (code 40720;50% patient expense), Complex Chuna (code 40721;80% patient expense), and Special Chuna (code 40730). Results During the period covered by health insurance, the number of CMT patients was 8,315,838, with 19,332,786 instances of CMT, and a total cost of 544,651,407 won. Due to COVID-19, the application of CMT decreased in the first quarter of 2020, but recovered from 2021, showing an increase in usage by the first quarter of 2023. The decline in the use of all medical institutions in the fourth quarter is believed to be due to restrictions on health insurance coverage for CMT. Conclusions Further research on CMT health insurance is necessary. This research should inform discussions on policies aimed at expanding health insurance coverage for CMT.

• 한국IT서비스학회:학술대회논문집
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• 한국IT서비스학회 2009년도 추계학술대회
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• pp.343-350
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• 2009

대규모 금융권 차세대 프로젝트에서 테스트에 대한 중요성은 재무RISK 관점에서 뿐만 아니라 소프트웨어 품질향상을 위한 결함의 제거 관점에서도 그 의미가 크다. 대규모 차세대 프로젝트는 일반 프로젝트에 비하여 개발되는 소프트웨어의 양이 방대하고 개발참여인원도 일반적인 관리수준을 넘어 수작업에 의한 테스트만으로는 충분한 품질을 보장하지 못한다. 또한 테스트를 수행한 이후에도 지속적으로 변경이 발생하고 이를 반영하는 과정에서 많은 결함이 유입되는 현재의 SI 프로젝트 특성상 지속적인 테스트 및 반복적인 검증만이 소프트웨어의 품질을 보장할 수 있다. 본 논문에서는 code coverage testing기법을 활용하여 동적 테스트 수행결과를 log로 도출하고, log 분석 결과를 통해 소프트웨어 품질의 향상을 기대할 수 있는 방안을 제시한다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2017년도 추계학술발표대회
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• pp.648-651
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• 2017

프로그램의 코드에 있어서 실행되지 않은 영역은 미지의 영역으로써 각종 에러와 오류의 잠재적 가능성을 지니고 있다. 개발자는 이러한 영역을 모두 검증, 테스팅 해봐야 이후 프로그램의 실행에서 예상치 못한 치명적 오류들에 대응할 수 있을 것이다. 우리는 본 논문에서 소프트웨어 테스팅의 두 가지 기법에 대하여 소개를 하고 이 두 가지를 이용하여 미실행된 영역을 실행시킬 수 있는 방법론을 제안하고자 한다. 실험에서 JaCoCo와 SPF를 사용하여 방법론을 적용하였고 이를 통하여 미실행 영역이 커버되는 테스트 케이스를 자동으로 얻어 낼 수 있었다.

• 전자공학회지
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• 제30권9호
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• pp.1002-1011
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• 2003

In this paper, we introduce an integrated SoC front-end design & verification environment which can be practically used in the embedded 32-bit processor-core SoC VLSI design. Our introduced SoC design & verification environment integrates two most important flows, such as the RTL power estimation and code coverage analysis, with the functional verification (chip validation) flow which is used in the conventional simulation-based design. For this, we developed two simulation-based inhouse tools, RTL power estimator and code coverage analyzer, and used them to adopt them to our RTL design and to increase the design quality of that. Our integrated design environment also includes basic design and verification flows such as the gate-level functional verification with back annotation information and test vector capture & replay environment.

• 한국컴퓨터정보학회논문지
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• 제21권11호
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• pp.159-166
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• 2016

Compiler course is one of the important courses in computer science. It requires more efficient learning environment because of its large coverage scale and complexity. One of its solutions is to provide the integrated development environment for educational compilers which is enable to give practice-oriented class and enhance student's interest. This paper presents the code generation support system developed in an integrated development environment of educational compiler. Our system helps students to understand the process of code generation and visualizes the relation among the source language, AST, and the target language. It makes students develop their own compilers more easily.

• Management Science and Financial Engineering
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• 제12권1호
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• pp.127-142
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• 2006

In this paper, we present a frequency reassignment problem (FRP) that arises when we add new base stations to resolve hot-spots or to expand the coverage of a code division multiple access (CDMA) network. For this problem, we develop an integer programming (IP) model along with some valid inequalities and preprocessing rules. Also, we develop an effective heuristic procedure that solves two sub-problems induced from the original problem in repetition. Computational results show that the proposed heuristic procedure finds a feasible solution of good quality within reasonable computation time. Also, the lower bound by-produced from the heuristic procedure is quite strong.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권9호
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• pp.3885-3906
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• 2020

Hybrid fuzzing which combines fuzzing and concolic execution, has proved its ability to achieve higher code coverage and therefore find more bugs. However, current hybrid fuzzers usually suffer from inefficiency and poor scalability when applied to complex, real-world program testing. We observed that the performance bottleneck is the inefficient cooperation between the fuzzer and concolic executor and the slow symbolic emulation. In this paper, we propose a novel solution named EPfuzzer to improve hybrid fuzzing. EPfuzzer implements two key ideas: 1) only the hardest-to-reach branch will be prioritized for concolic execution to avoid generating uninteresting inputs; and 2) only input bytes relevant to the target branch to be flipped will be symbolized to reduce the overhead of the symbolic emulation. With these optimizations, EPfuzzer can be efficiently targeted to the hardest-to-reach branch. We evaluated EPfuzzer with three sets of programs: five real-world applications and two popular benchmarks (LAVA-M and the Google Fuzzer Test Suite). The evaluation results showed that EPfuzzer was much more efficient and scalable than the state-of-the-art concolic execution engine (QSYM). EPfuzzer was able to find more bugs and achieve better code coverage. In addition, we discovered seven previously unknown security bugs in five real-world programs and reported them to the vendors.

• 한국IT서비스학회지
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• 제14권2호
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• pp.129-142
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• 2015

The purpose of this study is to suggest an effective regression testing method in order to minimize the scope of test resulting from the modification of software and to prevent mismatch of test case and test objects. As a way to improve the efficiency of regression testing which uses a change-centric testing technique, the method flow is analyzed and grasped through a static analysis based on source code in order to identify modified parts. After the order of priority is set according to the results of user action log-based dynamic analysis on identified regression testing objects, test effect can be raised by adjusting the order of priority using code complexity. Quality assurance coverage can be checked using the user action log suggested in this study, and the progress of test and whether or not each function has been verified can be checked, too. In addition, by minimizing test parts and adjusting the order of test, costs and time can be saved, making it possible to conduct regression testing effectively.