• 에너지공학
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• 제25권4호
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• pp.30-36
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• 2016

전동스쿠터용 배터리팩은 상온보다 고온일수록 내부저항이 감소하여 충전효율은 상승하나 배터리 안전성 문제로 인하여 냉각시스템을 필요로 한다. 본 연구의 목적은 냉각용 공기 흡입과 배출 방법과 시기를 다르게 하여 냉각 효율성을 분석하는 것이다. 배터리팩 내부에서 각각의 배터리 사이에 큰 온도편차가 존재하는 경우 배터리의 성능과 효율이 저감된다. 따라서, 배터리팩 냉각성능을 입-출구 냉각팬의 작동 방법 및 시기 변화에 의해 배터리의 성능과 효율을 개선시키도록 한다. 연구에 사용된 수치해석 상용코드는 17.0버젼의 ANSYS CFX이다.

• 한국융합학회논문지
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• 제9권10호
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• pp.237-242
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• 2018

마이크로 믹서는 랩-온-어-칩이나 마이크로 유체 기기의 하나의 구성품으로 두 가지의 화학 물질을 혼합(융합)하는 장치이다. 본 연구는 다양한 형상의 패시브 마이크로 믹서의 성능을 평가하는 것을 목적으로 한다. 다양한 형상의 마이크로 믹서는 총 6가지의 형상을 비교하였고, 서로 동일한 수력 직경을 갖도록 3차원 모델링하였다. 내부 혼합 유동을 전산모사하기 위해여 상용 유동해석 프로그램인 ANSYS Fluent를 사용하였다. 수치해석 방법은 본 논문에 자세하게 기술하였다. 마이크로 믹서의 성능 평가는 혼합 지수와 압력 강하로 비교하였고, 결론적으로 CDM-8T은 합리적인 혼합성능과 상대적으로 낮은 압력 강하를 갖는 것으로 나타났다.

• Advances in concrete construction
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• 제8권4호
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• pp.295-304
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• 2019

The lateral displacement or drift may be the cause of the damage in the reinforced concrete (RC) columns under the seismic load. In many regulations, lateral displacement was limited according to the properties of columns. The design displacement limits may be represented indirectly through the material strain limits and the mechanical properties of columns. EUROCODE-8 and FEMA356 calculate displacement limits by taking into account the mechanical properties of columns. However, Turkey Building Earthquake Code (TBEC) determine displacement limits by taking into account the material strain limits. The aim of this study is to assess the seismic design codes for RC columns through an experimental study. The estimates of seismic design codes have been compared with the experimental results. It is observed that the lateral displacement capacities of columns estimated according to some seismic codes are not in agreement with the experimental results. Also, it is observed that TBEC is conservative in the context of the performance indicator of RC columns, compared to EUROCODE-8 and FEMA356. Moreover, in this study, plastic hinge length and effective stiffness of test elements were investigated.

• 한국정보시스템학회지:정보시스템연구
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• 제23권3호
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• pp.99-125
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• 2014

Internet environment and innovative ICT(information and communication technology) have brought about big changes to our lifestyle and industrial structure. In spite of the convenience of Internet, various cyber incidents such as malicious code infection, personal information leakage, smishing(sms + phishing), and pharming have frequently occurred. Information security must be recognized as a key and compulsory element for surviving in a global economy. Strategic roles of information security have recently been increasing, but effective implementation of information security is still a major challenge to organizations. Our study examines the influencing factors of information security and investigates the causal relationship between information security maturity level and organizational performance through an empirical survey. According to the results of our study, personal, organizational, technical, and social factors affect organizations's information security maturity level altogether. This result suggests that when dealing with security issues, the holistic and multi-disciplinary approaches should be required. In addition, there is a causal relationship between information security maturity level and organizational performance, and organizations aim to establish the efficient and effective ways to enhance information security maturity level on the basis of the results of this study.

• 한국항해항만학회지
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• 제38권3호
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• pp.193-202
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• 2014

The comprehensive review of the STCW 1978, as amended in 1995 and associated Code was carried out from 2006 to 2010. These amendments will have a certain degree of impact on Maritime Education and Training(MET) institutes in terms of education and training of seafarer worldwide. Particularly, the Far East region countries are effected more than other regions since they covered about 30% of officers and 37% ratings in the world. In view of these facts this dissertation conceived to analyze the problems in the Far East main seafarer supply countries faced the implementation of "STCW Manila Amendments" To analyze these problems, this dissertation carried out questionnaire research to 7 targeted main MET of major Far East seafarer supply countries. After research this dissertation suggests the possible solutions such as, Joint On-Board Training Center; Joint Asia Maritime E-learning Systems; methods to reducing work-load, ship inspection burden and determine mandatory minimum safety manning standards in a safe way; technical cooperation fund to installation of training equipment; and clarify vague terminology of STCW Manila Amendments, to solve problems identified through the questionnaires.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.879-886
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• 2007

EPC (Electronic Product Code) tags and RFID (Radio Frequency IDentification) technology are said to have potential to change the ways individuals, organizations and societies operate on the everyday basis. In the near future, it is expected that every major retailer will use RFID and EPC systems to track the movement of products from suppliers to warehouses, store backrooms and eventually to points of sale. Recent efforts in EPC tags and RFID technology attempt to achieve an appropriate kind of interaction between technical and business areas. In this paper, we explore the fundamental characteristics of RFID and EPC applications and then review the different research studies of RFID technology and EPC system that have been proposed new theories and concepts that have emerged and utilized in different business fields of manufacturing and logistics. It provides an overview of the study achievements within the domain and critically evaluates the various approaches through the use of a case study and the construction of its comparison framework. The different research studies indicated that RFID and EPC systems will become more pervasive in the future and the changes that occur over the next few years will make for a further fascinating research area.

• 한국항공우주학회지
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• 제48권10호
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• pp.831-835
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• 2020

HLS는 C/C++ 언어로 기술된 소스 코드로부터 자동으로 HDL 코드를 생성하므로 타이밍이나 제어가 간단하고 하드웨어 구조를 쉽게 변경할 수 있어 FPGA 시스템 개발 기간을 단축할 수 있는 장점이 있다. 본 논문에서는 Xilinx사의 Vivado HLS를 이용하여 텔레메트리 표준 106-17 LDPC 부호기를 설계할 때 간단한 코드 수정으로 목적에 맞는 구조 변경의 용이함을 보이고 Spartan-7 xc7s100 디바이스를 타겟으로 합성하여 throughput과 하드웨어 복잡도 등의 결과를 비교하였다.

• 정보관리연구
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• 제26권2호
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• pp.61-79
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• 1995

정보검색의 성공여부는 적절한 검색어의 선정에 달려있다고 해도 과언이 아니다. 특히 CD-ROM이나 온라인목록시스템에서 주제검색시 분류표, 주제명과 같은 통제어와 자연어 등 비통제어의 비교 우위 문제는 아직도 논란이 되고 있다. 본고는 두 시스템의 검색효율성을 비교하기 위하여 특히 다언어 환경하에서의 검색어 사용에 중점을 두고 다양한 형태의 검색어휘를 조사 분석하였다.

• 한국유체기계학회 논문집
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• 제19권2호
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• pp.21-26
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• 2016

The objective of present study is to assess the performance of the first stage compressor in a total 3-stage 5000 HP-level turbo compressor. CFD commercial code, CFX has been used to predict three-dimensional flow characteristics inside of the impeller. Shear Stress Transport (SST) model has been used to simulate turbulent flows through Reynolds-averaged Navier-Stokes (RANS) equations. Grid dependency has been also checked to get optimal grid distribution. Numerical results have been compared with the experimental test results to elucidate performance characteristics of the present compressor. In addition, flow characteristics of the impeller only have been studied for various blade configurations. Angular offset in leading edge of the blade has been selected for the optimal blade design. Performance characteristics in region of low mass flow rate and high pressure ratio between the impeller entrance and exit have been investigated for the selection of optimal blade design. Also, flow instability such as stall phenomena has been studied and anti-stall characteristics have been checked for various blade configurations in the operational window.

• 디지털산업정보학회논문지
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• 제12권4호
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• pp.81-87
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• 2016

Recently, as the heterogeneous network (HetNet) has been deployed widely to support various kinds of Radio Access Networks(RANs) with a combination of Macro, Pico, and/or Femto cells, research and standardization efforts have been very active regarding the concept of Licensed Shared Access (LSA) for supporting spectrum sharing. In order for a mobile device to efficiently support the spectrum sharing, the mobile device shall be reconfigurable, meaning that its radio application code has to be adaptively changed in accordance with the hopping of desired spectral band. Especially, Working Group 2 (WG2) of Technical Committee (TC) Reconfigurable Radio System (RRS) of European Telecommunications Standards Institute (ETSI) has been a main driving force for developing standard architecture for Multi-mode Mobile Device (MD) that can be applied to the LSA system. In this paper, we introduce the Multi-mode MD architecture for supporting LSA-based spectrum sharing. An implementation of a test-bed of Multi-mode MD is presented in order to verify the feasibility of the standard MD architecture for the purpose of LSA-based spectrum sharing through various experimental tests.