• ETRI Journal
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• 제33권3호
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• pp.310-319
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• 2011

In this paper, a new soft-fusion approach for multiple-receiver wireless communication systems is proposed. In the proposed approach, each individual receiver provides the central receiver with a confidence level rather than a binary decision. The confidence levels associated with the local receiver are modeled by means of soft-membership functions. The proposed approach can be applied to wireless digital communication systems, such as amplitude shift keying, frequency shift keying, phase shift keying, multi-carrier code division multiple access, and multiple inputs multiple outputs sensor networks. The performance of the proposed approach is evaluated and compared to the performance of the optimal diversity, majority voting, optimal partial decision, and selection diversity in case of binary noncoherent frequency shift keying on a Rayleigh faded additive white Gaussian noise channel. It is shown that the proposed approach achieves considerable performance improvement over optimal partial decision, majority voting, and selection diversity. It is also shown that the proposed approach achieves a performance comparable to the optimal diversity scheme.

• Earthquakes and Structures
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• 제6권5호
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• pp.561-580
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• 2014

After strong earthquakes conventional frames used worldwide in multi - story steel buildings (e.g. moment resisting frames) are not well positioned according to reparability. Two innovative systems for seismic resistant steel frames incorporated with dissipative fuses were developed within the European Research Program "FUSEIS" (Vayas et al. 2013). The first, FUSEIS1, resembles a vertical Vierendeel beam and is composed of two closely spaced strong columns rigidly connected to multiple beams. In the second system, FUSEIS2, a discontinuity is introduced in the composite beams of a moment resisting frame and the dissipative devices are steel plates connecting the two parts. The FUSEIS system is able to dissipate energy by means of inelastic deformations in the fuses and combines ductility and architectural transparency with stiffness. In case of strong earthquakes damage concentrates only in the fuses which behave as self-centering systems able to return the structure to its initial undeformed shape. Repair work after such an event is limited only to replacing the fuses. Experimental and numerical investigations were performed to study the response of the fuses system. Code relevant design rules for the seismic design of frames with dissipative FUSEIS and practical recommendations on the selection of the appropriate fuses as a function of the most important parameters and member verifications have been formulated and are included in a Design Guide. This article presents the design and performance of building frames with FUSEIS 1-1 based on models calibrated on the experimental results.

• Coupled systems mechanics
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• 제3권1호
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• pp.1-25
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• 2014

In this work, we present the theoretical formulation, operator split solution procedure and partitioned software development for the coupled thermomechanical systems. We consider the general case with nonlinear evolution for each sub-system (either mechanical or thermal) with dedicated time integration scheme for each sub-system. We provide the condition that guarantees the stability of such an operator split solution procedure for fully nonlinear evolution of coupled thermomechanical system. We show that the proposed solution procedure can accommodate different evolution time-scale for different sub-systems, and allow for different time steps for the corresponding integration scheme. We also show that such an approach is perfectly suitable for parallel computations. Several numerical simulations are presented in order to illustrate very satisfying performance of the proposed solution procedure and confirm the theoretical speed-up of parallel computations, which follow from the adequate choice of the time step for each sub-problem. This work confirms that one can make the most appropriate selection of the time step with respect to the characteristic time-scale, carry out the separate computations for each sub-system, and then enforce the coupling to preserve the stability of the operator split computations. The software development strategy of direct linking the (existing) codes for each sub-system via Component Template Library (CTL) is shown to be perfectly suitable for the proposed approach.

• ETRI Journal
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• 제28권4호
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• pp.453-460
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• 2006

In this article, we introduce a new class of product codes based on convolutional codes, called convolutional product codes. The structure of product codes enables parallel decoding, which can significantly increase decoder speed in practice. The use of convolutional codes in a product code setting makes it possible to use the vast knowledge base for convolutional codes as well as their flexibility in fast parallel decoders. Just as in turbo codes, interleaving turns out to be critical for the performance of convolutional product codes. The practical decoding advantages over serially-concatenated convolutional codes are emphasized.

• 전자통신동향분석
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• 제14권2호통권56호
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• pp.38-52
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• 1999

우정업무는 발송인으로부터 우편물을 접수하여 수취인에게 배달하기 위해 소요되는 인력 의존도가 80%인 노동 집약적인 업무이다. 이에 따라, 우편고객에게 고품질의 우편서비스를 제공하기 위한 목적으로 우편물 자동구분 처리시스템을 개발하여 적용하고 있다. 본 고에서는 우편서비스의 질을 향상시키기 위한 노력의 일환으로 고객 바코드의 활용사례를 분석하고, 우편고객에게 부가서비스를 제공하기 위한 방법을 제시한 내용이다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.120-123
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• 1999

The precision cold forging process for steering yoke of automobile has been analysed by using rigid-plastic finite element analysis code DEFORM-3D Also the experiment has been performed through the optimized process. Until now steering yoke has been largely manufactured by hot forging or welding of forged head and shaft parts because of technical difficulty. the study has shown successful results of the precision cold forging through the proper selection of the process.

• 중소기업융합학회논문지
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• 제6권4호
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• pp.137-150
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• 2016

IT 기술 및 비즈니스의 급속한 발전에 따라 새로운 서비스를 고객에게 제공하기 위한 노력이 증가하고 있으며, 신속한 서비스 제공을 위해 기존의 레거시 시스템에 대한 개선 및 확장이 빈번히 발생하고 있다. 이로 인하여 기존 레거시 시스템에 대한 소스 코드의 품질 확보는 서비스 요구에 신속히 대응할 수 있는 핵심적인 기술 요소가 되었다. 리팩토링은 기존 레거시 코드에 대한 품질을 확보하기 위한 공학적 기술로서, 부가가치를 제공하는 레거시 시스템의 개선 및 확장에 필수적이다. 본 논문에서는 레거시 시스템의 소스 코드 품질 향상을 위한 기존의 리팩토링 기법과 지원 도구에 대한 조사 분석을 통해 리팩토링 기법과 도구에 대한 특성을 제안한다. 제안하는 특성을 기반으로 서비스 개발자가 레거시 시스템의 소스 코드 품질 향상을 위하여 리팩토링을 수행하고자 하는 경우, 어떠한 기법과 도구를 활용할 것인가에 대한 가이드라인을 제공받을 수 있다. 이를 통해 보다 정확하고 시행착오 없는 레거시 시스템의 소스 코드 품질을 향상시킬 수 있으며, 새로운 서비스에 대한 신속한 대응도 가능하게 될 것이다.

• 한국컴퓨터정보학회논문지
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• 제28권5호
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• pp.163-170
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• 2023

제4차 산업혁명의 가속화에 따라 해운산업에서는 자율운항선박(MASS)의 기술 개발 및 발전이 이루어지고 있으며, 이에 따른 국제 규정의 개발 역시 가속화되고 있다. 특히 IMO 해사안전위원회(MSC) 105차 회의에서는 회원 당사국 간 비강제적 자율운항선박 규정(MASS Code) 개발을 위한 로드맵을 수립하고 본격적으로 규정 개발에 착수하였다. 다수의 국가가 MASS Code 개발 작업에 적극적으로 참여하고 있으며, MASS Code에서 MASS 기능에 대한 상세한 요구사항에 대한 규정 개발 작업이 진행중이다. 특히, 자율운항선박의 자율도와 관련하여 "운항 모드(Mode of Operation)" 개념이 처음으로 언급되었으며, 2023년 4월에 개최될 IMO 자율운항선박 공동작업반(MASS JWG) 회의부터 이 운항 모드에 대한 논의가 진행될 것으로 예상된다. "운항 모드" 개념은 MASS 및 MASS 기능에 대한 설명과 더불어, MASS Code 개발을 위해 지속되어 논의될 것이다. 이 논문은 운항 모드 설정에 대한 기초연구를 수행하기 위해 운항 모드에 대한 지침을 제공하는 IMCA M 220 문서의 내용을 검토한다.

• 한국응용과학기술학회지
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• 제34권1호
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• pp.183-188
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• 2017

본 연구는 중 소형 선박의 배가스에 포함되어 있는 황산화물 및 질소산화물을 처리하기 위한 습식 스크러버의 처리효율에 관한 내용이다. 실험은 질소산화물 기술문서($NO_X$ Technical Code)의 E3 모드에 준해서 진행하였다. 엔진에서 황산화물을 배출하기 위해서, 연료로 사용되는 경유에 ditertiarybutyldusulfide를 혼합하여 황 함유량을 높인 연료로 실험을 진행하였다. 배가스 내의 질소산화물의 대부분을 차지하는 NO가스는 $NO_2$로 산화시켜 습식 스크러버로 흡수하였으며, 황산화물인 $SO_2$는 세정액에 잘 흡수되어 100% 처리효율을 확인하였다.

• 수산해양기술연구
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• 제46권4호
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• pp.487-494
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• 2010

In order to test the applicability of bunker-A in a diesel engine for small-fishing boat, the investigation of the engine performance and the exhaust emission was performed under various conditions of fuel property, intake air pressure and fuel temperature. It was also performed based on IMO NOx Technical code. At high load, the energy consumption rate of bunker-A was lower than that of diesel oil, and the characteristics of exhaust emission of bunker-A were similar to those, and NOx emission rates of both fuels satisfied the IMO NOx emission regulation limits. The energy consumption rate and characteristics of exhaust emission were improved as the intake air pressure was increased, but these were not improved remarkably as the temperature of bunker-A was heated. However, at low load the energy consumption rate, CO emission rate and HC emission rate of bunker-A were higher than those of diesel oil, but NOx emission rates of the fuels were about the same. In addition, at low load the energy consumption rate and CO emission rate of bunker-A were increased as the intake air pressure and the temperature were higher than normal conditions. Accordingly, it is thought that the use of bunker-A in a kind of test engine is possible at high load. On the other hand, it is thought that more research is needed to improve the combustion efficiency under low temperature and low load condition.