• 대한전기학회논문지:전력기술부문A
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• 제48권12호
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• pp.1575-1579
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• 1999

Embedded processors often accommodate two instruction sets, a standard instruction set and a compressed instruction set. With the compressed instruction set, code size can be reduced while instruction count (and consequently execution time) can be increased. To achieve code size reduction without significant increase of execution time, this paper proposes a new compressed instruction set architecture, called TOE (Two Operations Execution). The proposed instruction set format includes the parallel bit that indicates an instruction can be executed simultaneously with the next instruction. To add the parallel bit, TOE instruction format reduces the destination register field. The reduction of the register field limits the number of registers that are accessible by an instruction. To overcome the limited accessibility of registers, TOE adapts non-homogeneous register partition in which registers are divided into multiple subsets, each of which are accessed by different groups of instructions. With non-homogeneous registers, each instruction can access only a limited number of registers, but an entire program can access all available registers. With efficient non-homogeneous register allocator, all registers can be used in a balanced manner. As a result, the increase of code size due to register spills is negligible. Experimental results show that more than 30% of TOE instructions can be executed in parallel without significant increase of code size when compared to existing Thumb instruction set.

• 대한전기학회논문지:전력기술부문A
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• 제48권12호
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• pp.1564-1574
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• 1999

In order to improve the efficiency of optimizing compilers, integration of register allocation and instruction scheduling has been extensively studied. One of the promising integration techniques is register allocation based on register-reuse chains. However, the generation of register-reuse chains in the previous approach was not completely systematic and consequently it creates unnecessarily dependencies that restrict instruction scheduling. This paper proposes a new register allocation technique based on a systematic generation of register-reuse chains. The first phase of the proposed technique is to generate register-reuse chains that are optimal in the sense that no additional dependencies are created. Thus, register allocation can be done without restricting instruction scheduling. For the case when the optimal register-reuse chains require more than available registers, the second phase reduces the number of required registers by merging the register-reuse chains. Chain merging always generates additional dependencies and consequently enforces the execution order of instructions. A heuristic is developed for the second phase in order to reduce additional dependencies created by merging chains. For matrix multiplication program, the number of registers resulting from the first phase is small enough to fit into available registers for most basic blocks. In addition, it is shown that the restriction to instruction scheduling is reduced by the proposed merging heuristic of the second phase.

• 한국멀티미디어학회논문지
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• 제18권11호
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• pp.1319-1331
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• 2015

In the Republic of Korea, there's been a culture called 'Hyo' since Koryo Dynasty and this word represents the meaning of paying utmost respects to one's own parents and ancestors whether they are alive or have passed. However, nowadays, most of people live away from their family gravesites so that they do not and cannot take care of them except on the special holidays. For this reason, people could not respond promptly to the incidents occurred at the sites as they receive notifications much later dates most of the time. Thus, in this paper, we propose a low-cost gravesite monitoring system which the users can immediately respond to the disastrous events after being informed of current situations through PLC without delay. For the performance evaluation, the lab and test bed experiments were performed on an actual ship using 200Mbps and 500Mbps products instead of performing an on-site experiment after the system has actually been constructed. The Mountain Region PLC was installed on the power lines and the result showed successful 36.14Mbps communication. Therefore, we expect that this study will contribute in time and cost reduction while constructing the internet infrastructures in mountain regions or building the Smart-graves, tumulus, and charnel houses.

• Journal of Mechanical Science and Technology
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• 제20권5호
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• pp.652-657
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• 2006

Although many methods about the control of irregular external noise have been introduced and implemented, it is still necessary to design a controller that will be more effective and efficient methods to exclude for various noises. Accumulation of errors due to model tracking, internal noises (thermal noise, shot noise and 1/f noise) that come from elements such as resistor, diode and transistor etc. in the circuit system and numerical errors due to digital process often destabilize the system and reduce the system performance. New stochastic controller is adopted to remove those noises using conventional controller simultaneously. Design method of a model tracking dual controller is proposed to improve the stability of system while removing external and internal noises. In the study, design process of the model tracking dual stochastic controller is introduced that improves system performance and guarantees robustness under irregular internal noises which can be created internally. The model tracking dual stochastic controller utilizing F-P-K stochastic control technique developed earlier is implemented to reveal its performance via simulation.

• 전력전자학회논문지
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• 제14권4호
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• pp.299-306
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• 2009

최근 대기전력저감기능을 갖는 PWM IC를 적용한 플라이백 컨버터는 대기전력 모드 시 Burst 스위칭 동작에 의해 전력소모를 최소화 할 수 있지만 경 부하 및 대기전력모드 시 변압기를 통해 흐르는 큰 자화전류에 의해 여전히 낮은 효율특성을 가지는 문제점이 있었다. 본 논문에서는 경 부하 및 대기전력모드 동작 시 자화전류를 최 소화함으로 효율을 개선한 회로를 제안하였으며 50인치 PDP TV PSU (Power Supply Unit)에 있어서 대기전력 및 보조전원으로 사용된 70W 플라이백 컨버터에 적용 실험하여 보았다.

• 정보관리연구
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• 제31권4호
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• pp.71-87
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• 2000

최근 네트워크로 연결된 이기종의 유용성을 높이고 기존의 분산객체 컴퓨팅의 문제해결을 위해 이동 에이전트(Mobile agent)의 연구가 활발히 이루어지고 있다. 이런 연구를 통해 기존의 분산시스템뿐만 아니라 전자상거래, 네트워크관리, 정보검색 등 많은 분야에 이동 에이전트를 적용시키는 연구가 진행되고 있으며, 많은 시스템이 개발되고 있다. 본고에서는 에이전트의 연구에 있어 관련된 사항을 알아보고 에이전트간 통신기능향상을 위해 연구한 내용을 바탕으로 전반적인 내용을 다루고자 하며, 마지막으로 에이전트의 미래와 적용분야에 대해 다루고자 한다.

• 한국항해항만학회지
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• 제33권9호
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• pp.635-644
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• 2009

The optimum design of power yacht belongs to the nonlinear constrained optimization problems. The determination of scantlings for the bow structure is a very important issue with in the whole structural design process. The derived design results are obtained by the use of real-coded micro-genetic algorithm including evaluation from Lloyd's Register small craft guideline, so that the nominal limiting stress requirement can be satisfied. In this study, the minimum volume design of bow structure on the power yacht was carried out based on the finite element analysis. The target model for optimum design and local structural analysis is the bow structure of a power yacht. The volume of bow structure and the main dimensions of structural members are chosen as an objective function and design variable, respectively. During optimization procedure, finite element analysis was performed to determine the constraint parameters at each iteration step of the optimization loop. optimization results were compared with a pre-existing design and it was possible to reduce approximately 19 percents of the total steel volume of bow structure from the previous design for the power yacht.

• 공학교육연구
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• 제22권2호
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• pp.61-70
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• 2019

This paper deals with a 'Designeer' education program that has a specific objective of educating design to undergraduate students in mechanical engineering with the aim of enhancing their ability of collaboration with designers when they are going to work in the field after graduation. The entire curriculum of the Designeer education program is introduced first, the end of which two-semester Capstone Design Courses for senior students is offered to let them practice all the knowledge and skills in a project-based learning environment. Learning specific matters such as sketching & visual thinking, prototyping and user experience design is one thing and practicing those knowledge and skills into a Capstone Design project is another. At this point, design thinking process needs to be in place to give students a foresight of one-year journey and to ensure that they will produce a desirable, feasible and viable product at the end of the year when they define the right problem at the beginning. Their frustrations and discoveries while applying design thinking throughout the year is explained by taking an example of a Robot Vacuum Cleaner design project. Finally, we provide real examples of effective methods to practice divergent and convergent phases.

• Geomechanics and Engineering
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• 제37권1호
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• pp.31-48
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• 2024

To stabilize the excavations in urban area, soil anchorage is among the very common methods in geotechnical engineering. A more efficient deformation analysis can potentially lead to cost-effective and safer designs. To this end, a total of 116 three-dimensional (3D) finite element (FE) models of a deep excavation supported by tie-back wall system were analyzed in this study. An initial validation was conducted through examination of the results against the Texas A&M excavation cases. After the validation step, an extensive parametric study was carried out to cover significant design parameters of tie-back wall system in deep excavations. The numerical results indicated that the maximum horizontal displacement values of the wall (δ_hm) and maximum surface settlement (δ_vm) increase by an increase in the value of ground anchors inclination relative to the horizon. Additionally, a change in the wall embedment depth was found to be contributing more to δ_vm than to δ_hm. Based on the 3D FE analysis results, two simple equations are proposed to estimate excavation deformations for different scenarios in which the geometric configuration parameters are taken into account. The model proposed in this study can help the engineers to have a better understanding of the behavior of such systems.

• 콘크리트학회논문집
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• 제15권5호
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• pp.759-767
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• 2003

This paper presents the simplified but more rational analysis method for the prediction of additional internal forces induced in integral abutment bridges. These internal forces depend upon the degree of restraint provided tc the deck by the backfill soil adjacent to the abutments and piles. In addition, effect of the relative flexural stiffness ratio among pile foundations, abutment, and superstructure on the structural behavior is also an important factor. The first part of the paper develops the stiffness matrices, written in terms of the soil stiffness, for the lateral and rotational restraints provided by the backfill soil adjacent to the abutment. The finite difference analysis is conducted and it is confirmed that the results are agreed well with the predictions obtained by the proposed method. The simplified spring model is used in the parametric study on the behavior of simple span and multi-span continuous integral abutment PSC beam bridges in which the abutment height and the flexural rigidity of piles are varied. These results are compared with those obtained by loading Rankine passive earth pressure according to the conventional method. From the results of parametric study, it was shown that the abutment height, the relative flexural rigidity of superstructure and piles, and the earth pressure induced by temperature change greatly affect the overall structural response of the bridge system. It may be possible to obtain more rational and economical designs for integral abutment bridges by the proposed method.