• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.2
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• pp.108-116
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• 2002

In this paper, to improve bandwidth of microstrip antenna, we discussed the patch structure using dual patch and probe feed. To provide PCS service and IMT-2000 service simultaneous, a microstrip patch antenna needs impedance bandwidth of 22%. We propose wide-band microstrip path antenna without complexity. To analyze characteristics of microstrip patch antenna, we used Ensemble of commercial software. The microstrip patch antenna was designed, fabricated, and tuned. The result was that 500 ㎒(25.5%) of impedance bandwidth for VSWR 2,430 ㎒(21.9%) of impedance bandwidth for VSWR 1.5. The microstrip patch antenna has side lobe of -14 dB. The front to back ratio is 20 dB overall. The measured gain of the microstrip patch antenna is 5.2 dBi.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.7 s.349
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• pp.156-161
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• 2006

In this paper, an E-patch antenna on the U-shaped ground plane is designed and experimental studied. In order to reduce to cross-polarization level and to enhance the gain of the microstrip patch antenna, a U-shaped ground plane is employed in the microstrip patch antenna. As a main radiator, an E-shaped patch is used to reduce the antenna size as small as possible. Also to enhance the bandwidth of the antenna, a substrate of the lowest permittivity of which thickness as thick as possible is used and a rectangular patch is overlaid on the air substrate of the E-shaped patch antenna. The radiation characteristics of the antenna are calculated by CST Microwave Studio 5.0 simulation software. Experimental results show that by increasing the height of the sidewall of the ground plane, the antenna gain is increased and the cross-polarization level is decreased.

• Journal of Korean Society for Quality Management
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• v.39 no.2
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• pp.170-178
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• 2011

In general, a software fault detection phenonenon is described by a software reliability model based on a nonhomogeneous Poisson process(NHPP). In this paper, we propose a software reliability growth model considering the differences of the software environments in both the testing phase and the operational phase. Also, we consider the problem of determining the optimal release time and the optimal warranty period that minimize the total expected software cost which takes account of periodic software maintenance(e.g. patch, update, etc). Finally, we analyze the sensitivity of the optimal release time and warranty period based on the fault data observed in the actual testing process.

• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.115-122
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• 2018

As the proportion of software in weapon systems increases, the impact of software on the overall system is growing. As a result, software quality management becomes important, and related regulations and work manuals for quality assurance activities at each stage in the R & D process are becoming more sophisticated. However, due to the characteristics of the weapon system software that is developed as a customized form for the purpose of a specific mission, there are limits to specifying and definitizing the detailed requirements (upper and lower level) according to various operational concepts during the development process. Due to this, software modification (patch change, shape change due to upgrade, etc.) occurs on account of many defects and performance improvement in the mass production and operation stage after the development is completed. In this study, we analyze the characteristics of these weapon system softwares and propose quality improvement methods based on ISO / IEC / IEEE 29119 test method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.129-129
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• 2009

In this paper, a tunable microstrip patch antenna designed using RF MEMS switches is reported. The design and simulation antenna were performed using high frequency structure simulator (HFSS). The antenna was designed in ISM Band and operates simultaneously at 2.4 GHz and 5.7 GHz with a -10 dB return-loss bandwidth of 20 MHz and 180 MHz, respect-tively. To obtain high efficiency and improve integrated ability, the High Resistivity Silicon (HRS) wafer was used for the antenna. The antenna achieved high gain with 8 dB at 5.7 GHzand 1.5 dB at 2.4 GHz. The RF MEMS DC contact switches was simulated and analysis by ANSYS software.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.680-683
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• 2019

개발자의 부담을 줄이고 소프트웨어의 품질을 향상시키기 위해 APR (Automated Program Repair) 기술을 개선해야 할 필요가 있다. 현재 사용되는 대부분의 APR 기술은 개발자가 수작업으로 작성한 테스트 케이스를 통과하는 유효 패치(Valid Patch)를 만드는 방식을 사용하기 때문에 QoP(Quality of Patch)는 많이 뒤떨어지는 단점을 가지고 있다. 본 논문에서는 테스트 범위가 충분히 높은 테스트 케이스를 자동으로 생성하는 기술을 이용하여 기존의 유효 패치를 강화하는 기술을 제안한다. 제안하는 내용을 Defects4J 의 일부 프로젝트에 적용하여 기존 기법 대비 FL 의 성능은 유지하면서 기존에 찾지 못했던 유효 패치를 추가적으로 찾을 수 있음을 확인하였다.

• Proceedings of the Korea Information Assurance Society Conference
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• 2004.05a
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• pp.199-204
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• 2004

Operating systems and application programs have security vulnerabilities derived from the software development process. Recently, incident cases related with the abuses of these vulnerabilities are increasing and the damages caused by them are becoming very important security issues all over the nations. Patch management is one of the most important processes to fix vulnerabilities of softwares and to ensure a security of systems. Since an institute or a company has distributed hierarchical and heterogeneous systems, it is not easy to update patches promptly. In this paper, we propose patch management framework to safely distribute and install the patches on Windows, Linux, and Solaris client systems. Besides, we censidered extensibility and hierarchical structure for our patch management framework to support large scaled network environment.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.3
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• pp.173-173
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• 2004

In this paper, a wideband two-layer H-shaped microstrip antenna for WLAN is designed. To increase the bandwidth of microstrip patch antenna a configuration of stacked type using parastic element is used. Furthermore, to reduce the size of microstrip patch antenna, two techniques are employed . the first one is H-shaped patch type and the second one is that the main radiator and parastic patch are shorted to the ground plane using ten shorting posts. The antenna bandwidth and radiation characteristics are calculated by ENSEMBLE ver. 5.0 simulation software, and compared with the experimental results. Experiment results show that the bandwidth of antenna in 740㎒ centered at 5.46㎓(13.5%), which is close agreement with the calculations, 770㎒(13%). Also, the antenna size can be reduced by 71.5% compared with the half wavelength rectangular microstrip antenna using the same substrate at the same frequency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8A
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• pp.591-597
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• 2003

In this paper, a compact and broadband PIFA(Planar Inverted F Antenna) which has an additive short-circuit plate along the patch length was designed. For more compact PIFA short-circuit Plate along the patch width is reduced and an additive short-circuit plate along the patch length is used to broaden the bandwidth. The effect of an additive-short-circuit plate along the patch length was verified in single band PIFA and also verified in dual-band PIFA. The commercial software, IE3D, was used to design a PIFA and its performance was verified by comparing simulated results with measurement results.

• Journal of electromagnetic engineering and science
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• v.6 no.1
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• pp.36-46
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• 2006

In this paper, we present a two-element circularly-polarized antenna array for UHF-band RFID reader applications. The antenna element in the array is a comer-truncated rectangular patch placed on a thick plastic-foam dielectric. The patch is fed on one of its edges by a microstrip line printed on a separate thin substrate. The array antenna is fed by a microstrip power divider. Parametric studies on the patch are carried out, from which an optimum design of a single antenna element is derived. The element spacing and the feed network of the array are investigated. A commercial electromagnetic software is employed in the analysis and design of the antenna. The designed array is fabricated and tested. Measurements show good performance characteristics of the fabricated antenna: a 11.2-dBi gain, a reflection coefficient of - 14 dB, an axial ratio less than 3 dB over 3-dB beamwidths of 40 and 60 degrees on two principal planes.