• Journal of KIISE:Software and Applications
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• v.35 no.3
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• pp.149-161
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• 2008

As Programmable Logic Controllers(PLCs) are frequently used to implement real-time safety critical software, testing of PLC software is getting more important. We propose a structural testing technique on Function Block Diagram(FBD) which is one of the PLC programming languages. In order to test FBD networks, we define templates for function blocks including timer function blocks and propose an algorithm based on the templates to transform a unit FBD into a flowgraph. We generate test cases by applying existing testing techniques to the generated flowgraph. While the existing FBD testing technique do not consider infernal structure of FBD to generate test cases and can be applied only to FBD from which the specific intermediate model can be generated, this approach has advantages of systematic test case generation considering infernal structure of FBD and applicability to any FBD without regard to its intermediate format. Especially, the proposed method enables FBD networks including timer function blocks to be tested thoroughly. To demonstrate the effectiveness of the proposed method, we use trip logic of bistable processor of digital nuclear power plant protection systems which is being developed in Korea.

• The KIPS Transactions:PartA
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• v.18A no.6
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• pp.271-280
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• 2011

Time-Triggered Architecture (TTA), one of real-time software design paradigms which executes tasks in timely manner, has long been advocated as being better suited in fore-sighting system behavior than event-triggered architecture (ETA). To gain this valuable feature of TTA, however, precise task designing process is mandatory. Alternatively, ETA tries to execute tasks whenever paired events are occurred. It provides intuitive and flexible basement to add/remove tasks and, moreover, better response time performance. However ETA is difficult to analyze because system behavior might be different depending on the order of interrupts detected by the system. Many previous researches recommended TTA when developing safety-critical real-time systems, but cost problem of task designing process and insufficient consensus for applying rigorous software engineering practice are still challenging in practice. This paper describes software refactoring process which applying TTA approach into ETA based embedded software in artificial heart system. We implemented dedicated interrupt monitoring program to capture existing tasks' real-time characteristics. Based on the captured information, proper task designing process is done. Real-time analysis using RMA (Rate-Monotonic Analysis) verified that new design guarantees timeliness of the system. Empirical experiments revealed that revised design is as efficient, when measured in terms of system's external output, as the old design and enhances predictability of the system behavior as well.

• Journal of the Korean Vacuum Society
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• v.21 no.1
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• pp.62-68
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• 2012

The conversion efficiency of solar cells depending on incident angle of light is important for building-integrated photovoltaics (BIPV) applications. The quantum efficiency is the ratio of the number of charge carriers collected by the solar cell to the number of photons of a given energy shining on the solar cell. The analysis of angle dependence of quantum efficiencies give more information upon the variation of power output of a solar cell by the incident angle of light. The variations in power output of solar cells with increasing angle of incidence is different for the type of cell structures. In this study we present the results of the quantum efficiency measurement of single-crystalline silicon solar cells and a-Si:H thin-film solar cells with the angle of incidence of light. As a result, as the angle of incidence increases in single-crystalline silicon solar cells, quantum efficiency at all wavelength (300~1,100 nm) of light were reduced. But in case of a-Si:H thin-film solar cells, quantum efficiency was increased or maintained at the angle of incidence from 0 degree to about 40 degrees and dramatically decrease at more than 40 degrees in the range of visible light. This results of quantum efficiency with increasing incident angle were caused by haze and interference effects in thin-film structure. Thus, the structural optimization considering incident angle dependence of solar cells is expected to benefit BIPV.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.457-466
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• 1999

원자력 발전소 계측 제어 시스템, 의료 관련 시스템, 항공 관련 시스템 등 실생활과 밀접한 시스템에 소프트웨어의 사용이 점차 증가하고 있다. 이러한 시스템에서 소프트웨어의 오류는 예기치 않는 사고를 유발하여 인명, 재산상의 심각한 타격을 줄 수 있다. 그러므로 고신뢰도 소프트웨어의 개발 시에는 반드시 시스템의 안전성을 보장해 주어야 한다. 역방향 안전성 분석 방법은 시스템의 안전성을 분석하는 한가지 방법으로서 시스템의 위험 상태를 정의하고 그 위험의 원인들을 추적, 분석함으로써 안전성에 대한 효율적인 분석을 수행할 수 있는 장점을 갖는다. 이 논문에서는 소프트웨어 개발 초기 단계에서 안전성을 분석할 수 있는 방법으로 Colored Petri Nets(CPN)에 기반을 둔 역방향 안전성 분석 방법을 제시한다. 또한 CPN 역방향 안전성 분석 도구인 SAC(Safety Analyzer for CPN)의 설계 및 구현에 대해 언급한다. SAC은 기존의 상용 CPN 모델링 도구인 Design/CPN과 연계하여 사용될 수 있으므로 CPN으로 모델링된 시스템의 안전성을 분석할 수 있다는 장점이 있다. 이 논문에서는 예제로 자동 교통 제어 시스템의 일부를 CPN으로 모델링하고 SAC을 이용한 분석 과정을 기술한다.Abstract In safety-critical systems such as nuclear power plants, medical machines, and avionic systems which are closely related with our livings, the usage of software in the controlling part is growing rapidly. Since software errors in safety-critical systems may cause serious accidents leading to financial or human damages, system safety should be ensured during and after development of a system. A backward safety analysis technique defines system hazards and tries to trace their causes by analyzing system states backward. In this paper, we provide a backward safety analysis technique based on Colored Petri Nets(CPN), which is applicable to the early software development phase. Also Safety Analyzer for CPN(SAC), the supporting tool, is designed and implemented. Since SAC is compatible with Design/CPN, a commercial tool for supporting CPN, it can be applicable to analyze safety in practical problems. As an example, we model a part of the traffic light control system using CPN and analyze safety properties of the model using the SAC tool.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.3
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• pp.23-40
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• 1997

There are a lot of security tools for the investigation and improvement of UNIX systems. However, most of them fail to provide a consistent and usable user interface. In addition, they concentrate on a specific aspect of a system, not the whole one. For the overall management, system administrators cannot help using several uncomfortable tools. This paper introduces an integrated security analysis tool, named "Zkimi", which provides a convenient user interface and investigates the various aspects of UNIX systems such as account security, system security, network security, and file system integrity. The Zkimi supports user-friendly WWW based interface, so administrators can examine the various aspects of system more easily. We tried the tool for a system of a moderate size, and were confirmed that the tool is very efficient for investigating various security aspects of a system. a system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.2
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• pp.111-122
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• 2002

Malicious attackers generally attempt to intrude the target systems by taking advantage of existing system vulnerabilities and executing readily available code designed to exploit blown vulnerabilities. To the network security administrators, the rat and minimal step in providing adequate network security is to identify existing system vulnerabilities and patch them as soon as possible. Network-based vulnerability analysis scanners (NVAS), although widely used by network security engineers, have shortcomings in that they depend on limited information that is available and generally do not have access to hast-specific information. Host-based vulnerability analysis scanner (HVAS) can serve as an effective complement to NVAS. However, implementations of HVAS differ from one platform to another and from one version to another. Therefore, to security engineers who often have to maintain a large number of heterogeneous network of hosts, it is impractical to develop and manage a large number of HVAS. In this paper, we propose an agent-based architecture named ISMAEL and describe its prototype implementation. Manager process provides various agent processes with descriptiom on vulnerabilities to check, and an agent process automatically generates, compiles, and executes an Java code to determine if the target system is vulnerable or not. The result is sent back to the manager process, and data exchange occurs in % format. Such architecture provides maximal portability when managing a group of heterogeneous hosts and vulnerability database needs to be kept current because the manager process need not be modified, and much of agent process remains unchanged. We have applied the prototype implementation of ISMAEL and found it to be effective.

• Weed & Turfgrass Science
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• v.6 no.1
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• pp.11-20
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• 2017

Ninety species belonging to 28 families of weeds were identified in Korean rice fields. They were divided by eight provinces and 19 agro-climatic zones to be used as basic data of weed control. Looking at the regional weed occurrence, there were 52 species of 20 families in Gyeonggi, 37 species of 17 families in Gangwon, 41 species of 15 families in Chungbuk, 21 species of 12 families in Chungnam, 24 species of 13 families in Jeonbuk, 54 species of 21 families in Chonnam, 36 species of 20 families in Gyeongbuk, and 32 species of 16 families in Gyeongnam province, respectively. The most dominant family was Poaceae followed by Cyperaceae and Asteraceae. Mostly dominant species were Echinochloa spp., Monochoria vaginalis var. plantaginea, Scirpus juncoides var. hotarui, Eleocharis kuroguwai, and Sagittaria sagittifolia subsp. leucopetala with slight differences among the provinces. Although there were some differences in 18 climate zones from Taebaek sub-highlands to the southern part of the East Coast (except for the Taebaek Highland), the dominant species were Echinochloa spp., Monochoria vaginalis var. plantaginea and Scirpus juncoides var. hotarui. The most dominant family was Cyperaceae followed by Poaceae and Asteraceae. The differences of weed occurrence between provinces and agro-climatic zones were largely influenced by various weather conditions rather than the provinces. The changes in cultivation mode and herbicide use might influence as well.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.12 no.1
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• pp.125-137
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• 2001

We investigated the self-concept, subjective depression, and state-trait anxiety of the school boys with learning disabilities(abbr. LD, n=86) and compared them with normal boys(n=52) using Piers-Harris Self-Concept Inventory, Child Depression Inventory(abbr. CDI), and State-Trait Anxiety Inventory(abbr. STAI). With regard to Piers-Harris Self-Concept Inventory total scores, there was no significant difference between two groups, but normal boys showed higher scores in intellectual and school status, physical appearance, and happiness-satisfaction subscales than patients with LD. The male patients with LD showed significantly higher ratings in CDI total scores, and CDI subscales - ineffectiveness, anhedonia, negative self-esteem than normal children. The patients with LD reported significantly higher state anxiety, but not trait anxiety. Correlation analyses revealed that self-concept decreased over time, and depression-anxiety increased across grades in the patients with LD, but not in normal children. Especially, negative mood, anhedonia, negative self-esteem subscales of CDI, and state-trait anxiety showed significant positive correlation with grades. In both groups, CDI scores were inversely correlated with Piers-Harris Self-Concept and positively with State-Trait anxiety. In conclusion, self-concept problems which were related with school achievement and self-esteem were more abundant in the patients with LD than normal children, self-image problem, depression and anxiety increased across grades. According to regression analysis, age, behavior subscale, intellectual-school status, anxiety, popularity, happiness-satisfaction, CDI-ineffectiveness, interpersonal problem, negative self-esteem, and state anxiety could explain the self-concept in the patients with LD, not in normal children. So, the self-concept of the patients with LD were found to be related to the school achievement and stress when comparing with peers. In conclusion, elementary school boys with LD showed lower self-concept, higher depression and anxiety, and these differences increased across grades. Since the patients with LD have concomitant depression and anxiety disorders, it is important that comorbidity with emotional problems should be explored and managed properly.

• Journal of agriculture & life science
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• v.51 no.3
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• pp.19-27
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• 2017

This study was conducted to investigate the optimum transplanting method for increasing the rice yield and quality by early transplanting cultivation in Gyeongnam plain area. This examination used of the transplanting method of planting distance($30{\times}14$ and $30{\times}18cm$) with number of seedlings(3, 5 and 7 plants). In high planting density($30{\times}14cm$), the number of tillers was increased while plant height was decreased as the planting number increases. On the other hand, the plant height and number of tillers were increased as planting number increases in low planting density($30{\times}18cm$). However, the number of grain per panicle was increased while the number of panicle was decreased as the planting number decreases. The number of panicle and the number of grain per panicle was increased as the planting distance increase. The yield of rice, when transplanted in the distance of $30{\times}14cm$ with 3 plants, was higher than the other treatment. Head rice ratio and head rice yield was the highest when transplanted in the distance of $30{\times}18cm$ with 3 plants(403 kg/10 a). The protein content was decreased and Toyo taste value was improved when transplanted in the distance of $30{\times}18cm$. Taken together, the best transplanting method for early transplanting cultivation was low planting density($30{\times}18cm$) with 3 plants in Gyeongnam plain area.

• Journal of agriculture & life science
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• v.53 no.2
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• pp.87-95
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• 2019

This study was carried out to select the rice variety for high quality rice according to reducing N application level (7 kg/10 a) in medium altitude and plain of southern Korea. It was cultivated to seven varieties and ten varieties in medium altitude and plain region respectively in this study. In medium altitude region, the yield of head rice was higher in most varieties except for Borami (526 kg/10 a) than the control variety, Chucheongbyeo (533 kg/10 a). On the other hand, Borami, Gopumbyeo, and onnuri were lower in head rice rate than the other varieties. In addition, Borami and Chucheongbyeo shown a lodging risk but the other varieties were safe against lodging. The milled rice protein content of Chucheongbyeo was 6.1% and the other varieties protein content was similar or lower than that of control except for Borami(6.3%). In plain region, the head rice yield of Nampyeongbyeo (527 kg/10 a) was higher than that of control variety, Ilmibyeo (503 kg/10 a). Head rice rate was lower in Hopumbyoe, Sindongjin, and Chilbobyeo than the other varieties. The varieties contained lower protein content compared Ilmibyeo (6.1%) were Hopumbyeo (5.9%), Jinsumi (6.0%), Sindongjin (5.9%), Chilbobyeo (6.0%), Hwangeumnodeul (5.8%), Hopyeongbyeo (6.0%). Amylose content, whiteness, and palatability (Toyo value) were no significant difference among varieties in two different regions. In conclusion, considering head rice rate, yield of head rice, protein content, lodging resistance, ripening rate and palatability, Pungmi1ho, Saenuri, Chilbobyeo in medium altitude region and Jinsumi, Hwanggumnodul in plain region were selected as proper rice varieties for high quality rice production in southern Korea.