• Structural Engineering and Mechanics
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• 제88권1호
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• pp.43-52
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• 2023

This paper handles the results of an extensive parametric study on the rotational stiffness of the flexible base connection using ABAQUS program. The results of the parametric study show the relation between the applied moment and the relative rotation for 96 different base connections. The configurations of the studied connections considered different numbers, diameters, and spacing of the anchor bolts along with different thicknesses of the base plate to investigate the effect of these parameters on the rotational stiffness behavior. The results of the previous parametric research used through the whale optimization algorithm (WOA) to detect different equation formulation of the moment-rotation (M-Ɵ_r) equation to detect optimum equation simulates the general nonlinear rotational behavior of the flexible base connection considering all variables used in the parametric study. WOA is a relatively new promising algorithm, which is used in different types of optimization problems. For more verification, the classical genetic algorithm (GA) is used to make a comparison with WOA results. The results show that WOA is capable of getting an optimum equation of the M-Ɵ_r relation, which can be used to simulate the actual rotational stiffness of the flexible base connections. The rotational stiffness at H/150 can be calculated using WOA (1) method and be used as a design aid for engineering design.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.551-556
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• 2004

The Korean Train eXpress(KTX) which started in last April has got many complaints of passengers. This is caused by weak connections between KTX and traditional trains. This paper shows the methods to increase the connection in 3 points of view; business, operation and rolling stocks. For the flexible business, it is necessary that the connecting trains must be multi-purposefully for the satisfaction of KTX transferring passengers and existing commuting passengers. And the expanding of free class is needed. A free class is the base of business flexibility. In an operation point of view, I show the method that can decrease pains for getting transfer. Finally, for the effective using of rolling stocks, I propose that TC(trailer with control) car is added to existing locomotive and passenger coach set. In concluding, KTX needs strong connections with traditional trains. This will bring more competitive power with other transportation systems. And that method must get flexible and various service, in addition to effective and minimizing investment.

• Steel and Composite Structures
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• 제1권4호
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• pp.459-480
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• 2001

The damage suffered by steel structures during the Northridge (1994) and Kobe (1995) earthquakes indicates that the fully restrained (FR) connections in steel frames did not behave as expected. Consequently, researchers began studying other possibilities, including making the connections more flexible, to reduce the risk of damage from seismic loading. Recent experimental and analytical investigations pointed out that the seismic response of steel frames with partially restrained (PR) connections might be superior to that of similar frames with FR connections since the energy dissipation at PR connections could be significant. This beneficial effect has not yet been fully quantified analytically. Thus, the dissipation of energy at PR connections needs to be considered in analytical evaluations, in addition to the dissipation of energy due to viscous damping and at plastic hinges (if they form). An algorithm is developed and verified by the authors to estimate the nonlinear time-domain dynamic response of steel frames with PR connections. The verified algorithm is then used to quantify the major sources of energy dissipation and their effect on the overall structural response in terms of the maximum base shear and the maximum top displacement. The results indicate that the dissipation of energy at PR connections is comparable to that dissipated by viscous damping and at plastic hinges. In general, the maximum total base shear significantly increases with an increase in the connection stiffness. On the other hand, the maximum top lateral displacement $U_{max}$ does not always increase as the connection stiffness decreases. Energy dissipation is considerably influenced by the stiffness of a connection, defined in terms of the T ratio, i.e., the ratio of the moment the connection would have to carry according to beam line theory (Disque 1964) and the fixed end moment of the girder. A connection with a T ratio of at least 0.9 is considered to be fully restrained. The energy dissipation behavior may be quite different for a frame with FR connections with a T ratio of 1.0 compared to when the T ratio is 0.9. Thus, for nonlinear seismic analysis, a T ratio of at least 0.9 should not be considered to be an FR connection. The study quantitatively confirms the general observations made in experimental results for frames with PR connections. Proper consideration of the PR connection stiffness and other dynamic properties are essential to predict dynamic behavior, no matter how difficult the analysis procedure becomes. Any simplified approach may need to be calibrated using this type of detailed analytical study.

• Journal of Communications and Networks
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• 제13권1호
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• pp.70-76
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• 2011

This paper presents the unified user equipment (UE) baseband modulation and demodulation (modem) hardware platform architecture to support multiple radio access technologies. In particular, this platform selectively supports two systems; one is HEDGE system, which is the combination of third generation partnership project (3GPP) Release 7 high speed packet access evolution (HSPA+) and global system for mobile communication (GSM)/general packet radio service (GPRS)/enhanced data rates for GSM evolution (EDGE), while the other is LEDGE system, which is the combination of 3GPP Release 8 long term evolution (LTE) and GSM/GPRS/EDGE. This is done by applying the flexible pin multiplexing scheme to a hardwired pin mapping process. On the other hand, to provide stable connection, high portability, and high debugging ability, the stacking structure is employed. Here, a layered board architecture grouped by functional classifications is applied instead of the conventional one flatten board. Based on this proposed configuration, we provide a framework for the verification step in wireless cellular communications. Also, modem function/scenario test and inter-operability test with various base station equipments are verified by system requirements and scenarios.

• Journal of Computational Design and Engineering
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• 제3권4호
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• pp.363-369
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• 2016

Cyber Physical System (CPS) and Internet of Things (IoT) are hot objects of interest as an extension of the embedded system. These interactive products and systems contain Mobile Devices which are most popular and used most frequently. Also these have been widely used from the control of the Nuclear Power Control System (NPCS) to IoT Home Service. Information & Communication Technology (ICT) topics of trend fused-complex current Information Technology (IT) and Communication Technology (CT) are closely linked to real space and virtual space. This immediately means the arrival of the ultra-connected society. It refers to a society in which various objects surrounding the human innovation and change in the social sector are expected through the connection between the data which are to be generated. In addition, studies of Tool-kit for the design of such systems are also actively pursued. However, only increased cooperation and information sharing between the physical object consists of a variety of machinery and equipment. We have taken into consideration a number of design variables of the high barriers to entry about the product. In this study, It has been developed a Web-based collaboration framework which can be a flexible connection between macroscopically virtual environment and the physical environment. This framework is able to verifiy and manage physical environments. Also it can resolve the bottlenecks encountered during the base expansion and development process of IoT (Internet of Things) environment.

• 한국조경학회지
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• 제30권2호
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• pp.50-62
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• 2002

From modernism to post-modernism, the practice in the design field often reduced the complexity of environment and to remove variety. However, contemporary ideas of space have been changed. The current thought premise is that the environment is mutable and is evolving according to inner and outer forces and elements. Therefore, leading designers recognize that the environment is complex in itself while anticipating a new theory explaining on-going trends. The idea of fold formulated by Gilles Deleuze can provide a theoretical base for new environmental design in constrat to current design practices. The fold is a hybrid by accommodating complex relations within an object. It carries a dynamic world view through continual process and yields a topological space against absolute space like Euclid geometry. The characteristics of the fold can be paraphrased as rhizome, stratification and smooth space. Rhizome forms a non-hierarchial connection like networking in internet space. Stratification is a kind of superimposition of autonomous potential layers within a single object. Smooth space is a free space and event oriented space keeping non-linear form. This study tried to incorporate the idea of fold to environmental design methods and design process in order to make space which can correspond with complex environment and topological form. In the design process adapted to fold theory, rhizome analysis accepts the complexity of environment and stratification strategy embraces the possibility of accidental use. As a result, the designed park carries a monadic image and produces an ambiguous space. Lastly, smooth space makes topological space unlike Euclid geometry and is free space comosed by the user themselves. Transporting the idea of fold into environmental design could be an alterative way for indeterminate and flexible design to accept new identity of place. Therefore, this study accepts the concept of incidental morphogenesis to make space based on the complexity of environment. The designed space based on the idea of fold searches to create free event space determined by user rather than designated by designer.

• 전자공학회논문지S
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• 제35S권6호
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• pp.36-45
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• 1998

본 논문은 고속의 비동기 전송 방식인 ATM 서비스를 무선 서비스에 수용하기 위한 다중 접근 제어 방식에 대한 내용이다. 무선 ATM 망에서는 유선 망에서 제공되고 있는 음성, 컴퓨터 데이터 및 비디오 같은 다양한 형태의 사용자 요구에 대하여 서비스 질을 만족시키면서 수용하는 것이 가장 중요한 요구사항으로 전제되어야 있다. 기본적으로 이러한 요구 사항을 효과적으로 수용하기 위해서는 기지국에서의 중앙 제어 방식이 바람직한 것으로 제시되고 있다. 본 논문에서 제안된 매체접근 방법은 단말로부터의 데이터 전송요구에 대하여 기지국이 동적으로 자원을 허가하는 방식이다. 본 방식에서는 동적 자원 할당을 위해 트래픽 설정 단계에서 제공되는 트래픽 특성 및 QoS 정보와 기지국에서 관리되는 타임 스템프 정보를 이용하는 방법을 제시한다. 이런 자원할당 방법을 적용함으로써 다양한 전송 속도와 QoS 제한치를 필요로 하는 통합된 형태의 서비스 요구에 매우 융통성 있고 효과적으로 대처할 수 있다. 그리고 시뮬레이션을 통해 주어진 환경하에서의 서비스 질과 성능적인 요소들을 확인할 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.417-420
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• 2006

최근 유 무선 홈 네트워크를 위한 다양한 기술들이 개발되고 있는데, 이러한 기술들을 수용하여 댁내 유무선 정보가전기들을 인터넷을 통해서도 통합제어 가능한 효율적인 미들웨어를 필요로 한다. UPnP(Universal Plug and Play)는 기본적으로 표준 TCP/ 프로토콜에 근거하여 PnP(Pulg and Play)개념을 네트워킹에 확장한 것이다. 지능형 가전, 무선기기 및 모든 종류의 PC들을 연결하기 위한 파급력이 있는 P2P(Peer to Peer) 네트워크 연결 구조를 지닌다. UPnP는 TCP/IP를 기본으로 하여 댁내 정보가전들을 통합제어 하기 위한 홈 네트워크 미들웨어로 제시되어 상용화되고 있지만 그 한계가 내부 네트워크에 국한되고 기능의 한계와 다른 기기들을 제어하기가 힘들다. 본 논문에서는 인터넷 홈 네트워크 가전 제어를 위해 UPnP를 확장하여 인터넷 게이트웨이를 통하여 인터넷망을 통하여 서로간의 모든 기능 및 컨트롤이 가능한 시스템을 구축을 연구한다.

• 한국항만경제학회지
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• 제25권3호
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• pp.165-182
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• 2009

본 연구에서는 부산지역의 ICD의 역할과 기능을 활성화하기 위하여 제3자물류 방식인 TPL(Third Party Logistics) 서비스의 기능을 활용하고 이를 적극적으로 개발하기 위한 방안에 대하여 제시하고 관련 이슈를 논의하였다. Oum Park(2004)과 Lu(2003)의 연구를 통하여, 국제유통센터의 운영자들은 화주들의상이한 욕구를 정확하게 파악해야 하며, 이러한 욕구의 만족을 통해 이익을 창출해야한다고 주장하였다. 이러한 항만배후단지 입지 선정요인에 대한 문헌연구와 이를 바탕으로 시너지 효과를 발휘할 수 있는 TPL 서비스인 제3자 물류기업 유치방안을 전략적 차원에서 1) 항만배후단지의 경쟁우위 및 개선사항, 2) ICD 물류기업 유치전략, 3) 저렴한 항만배후단지 임대료, 4) 조세혜택 및 인센티브, 5) 부지확보 및 기반시설 확충, 6) 원활한 물류서비스 제공, 7) 물류기업의 연계방안 구축, 8) 차별화된 인센티브 전략 수립, 9) 장기적인 마케팅 활동 중심으로 제시하고 ICD에서 제3자 물류기업을 유치할 수있는 유치업종과 정부의 정책적 지원방안에 대하여 논의하였다. 본 연구는 부산지역의 ICD의 활로모색과 부산항의 항만배후지의 적극적 활용방법의 모색이라는 두 가지 탐색적 측면에서의 기여도를 제공한다. 특히, TPL 서비스인 제3자 물류기업 유치방안과 ICD에서 제3자 물류기업을 유치할 수 있는 유치업종 제시를 위한 기초토대를 제공하는데 연구의 목적이 있다. 본 연구의 한계점으로 첫째, TPL 서비스인 제3자 물류기업 유치방안을 통하여 ICD에서 제3자 물류기업을 유치할 수 있는 유치업종 제시를 위한 기초토대를 제공하는데 연구의 목적이 있음으로, 좀 더 분석적 시각에서 실증분석을 통하여 향후 연구를 위한 이론적 토대와 통계적 분석방법이 제시될 필요가 있다. 둘째, TPL 서비스인 제3자 물류기업 유치방안은 기업의 전략적 측면뿐만 아니라 정부의 정책적 측면도 성공의 중요한 요인이 됨으로 향후 연구에서는 정부의 정책적 측면에 관련된 자료와 균형적 감각의 분석이 요구된다.