• Proceedings of the IEEK Conference
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.331-334
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• 1998

In this paper, we have presented an improved design of the microwave level meter based on the principle of FM-CW radar. First, we have analyzed the effect of VCO nonlinearity on the spectral broadening of the beat signal, and presented a new type of design theory to linearize VCO tuning curve adopting FFT algorithm. Simulation results for a VCO having the linearity of 25% have been presented, which show the usefulness of the design algorithm.

• International Journal of Contents
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• 제10권4호
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• pp.53-62
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• 2014

Although many studies have considered the outcomes and impacts of serious games, little is known about the factors which affect a user's perception or interpretation in games during the process of decision making from theoretical perspectives. This study aimed to explore the process of user perception from the perspective of construal level theory, and to suggest a theoretical design approach for the development of effective serious games. In the current study, cognitive and affective learning outcomes were articulated through literature review and synthesized into a series of assumptions with persuasive and educational aspects in serious games. Serious games reflect the potential of the game mechanism for changing players' perception, and helping with knowledge acquisition of the users. The potential to use construal level theory for effective serious games interventions was suggested, and a Serious Games Design Framework was proposed via potential outcomes from recent advanced research. Finally, implications of the application of the suggested model with various-related purposes and directions for future research were discussed. The model could be useful not only for game researchers and designers, but also for game marketers in attracting potential consumers.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1302-1313
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• 2010

The west express way is notorious for extremely heavy traffic area in the west of Seoul, South Korea. Hence, the city government recently initiated a new underground BTO (Build-Transfer-Operate) road project to solve traffic congestion and a high construction cost. The proposed underground express road being designed is the first double-level tunnel ever designed in South Korea and using Conventional tunnelling method (NATM). A total length of tunnel for light vehicles is 10.91km long including both open cut structures and concrete lining with middle-deck in bored tunnel. There are also 4 ventilation shafts for ventilation and evacuation on emergency. Many design issues had been aroused during the preliminary design phase and detail design phase is currently going on. This paper discusses design focuses including excavation methods, ground water issues, a deck slab installation, and a construction cost etc. for the double level road tunnel design of urban area.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.363-368
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• 2002

A practical implementation method of squeeze-film aeroelastic disk vibration damping and its practical design performance are presented to provide a solution method to meet the tight TMR(Track Mis-Registration) design budget of high-TPI HDDs. Most previous research results are mainly based on the component-level study in the 'open-cover state' which is far from the realistic operation HDD condition. In this study, the squeeze-film disk damping effect is widely investigated under the realistic drive-level condition of 'enclosed-cover state.' It is found that the proper aeroelastic gap(s) between disk(s) and adjacent surface(s) to give significant vibration reduction in the enclosed HDD operating conditions can be achieved not only by classical well-known squeeze-film damping gaps such as very small 0.0x-millimeter level gaps which are not practically implementable in mass-production HDDs, but also by a few 0.x millimeter which is possible for designing realistic HDD design. The various experimental results including drive-level PES are also presented to prove feasibility of the optimal disk damper design for 93kTPI HDDs.

• Journal of the Microelectronics and Packaging Society
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• 제18권2호
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• pp.35-41
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• 2011

Recently, board level solder joint reliability performance of IC packages during drop impact becomes a great concern to semiconductor and electronic product manufacturers. The handheld electronic products are prone to being dropped during their useful service life because of their size and weight. The IC packages are susceptible to solder joint failures, induced by a combination of printed circuit board (PCB) bending and mechanical shock during impact. The board level drop testing is an effective method to characterize the solder joint reliability performance of miniature handheld products. In this paper, applying the JEDEC (JESD22-B111) standard present a finite element modeling of the FBGA. The simulation results revealed that maximum stress was located at the outermost solder ball in the PCB or IC package side, which consisted well with the location of crack initiation observed in the failure analysis after drop reliability tests.

• Journal of Korean Society of Coastal and Ocean Engineers
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• 제21권3호
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• pp.224-229
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• 2009

Partial safety factors(PSFs) for Level I reliability based design of caisson type quay walls were calculated. First order reliability method(FORM) based PSFs are the functions of sensitivities of limit state function with respect to design random variables, target reliability index, characteristic values and first moment of random variables. Modified PSFs for water level and resilient water level are newly defined to keep consistency with the current design code. In the numerical example, PSFs were calculated by using a target reliability index. Seismic coefficient is defined to show extreme distribution. It was found that PSFs for seismic coefficient becomes smaller as the return period for design seismic coefficient grows longer.

• Journal of Korea Game Society
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• 제11권2호
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• pp.19-28
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• 2011

Level design is one of the important factors in tower defense game development. The difficulty of tower defense game depends on its wave design. In general, it requires a lot of manual labor to generate well-balanced waves with fun. In this paper, we propose a new automated wave generation system by using a genetic algorithm. With our system, a game designer can easily generate an optimized wave by designating the difficulty level in the initial stage of game design. Our system can be useful in reducing the trial-errors in the initial level design process of tower defense game development.

• The Transactions of the Korean Institute of Power Electronics
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• 제25권6호
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• pp.442-450
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• 2020

A small-signal modeling approach for a three-level boost (TLB) converter and a design methodology for a double-loop controller are proposed in this study. Conventional modeling of TLB converters involves three state variables. Moreover, TLB converters have two operation modes depending on the duty ratio. Consequently, complex mathematical calculations are required for controller design. This study proposes a simple system modeling method that uses two state variables, unlike previous methods that require three state variables. Analysis shows that the transfer functions of the two operation modes can be expressed as identical equations. This condition means that the linear feedback controller can be applied to all operational ranges, that is, for full duty ratios. The design method for a double-loop controller using a PI controller is presented in step-by-step sequences. Simulation and experimental verifications are conducted to verify the effectiveness of the small-signal analysis and control system design.

• Journal of KIISE:Computer Systems and Theory
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• 제34권8호
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• pp.327-336
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• 2007

Lots of effort toward design optimizations have been paid for a cost-effective system design in various ways from a transistor level to RTL designs. In this paper, we propose a bit level optimization of an adder design for expanding its design space. For the bit-level optimization, a heterogeneous adder organization utilizing a mixture of carry propagation schemes is proposed to design a delay-area efficient adder which were not available in an ordinary design space. Then, we develop an optimization method based on Integer Linear Programming to search the expanded design space of the heterogeneous adder. The novelty of the Proposed architecture and optimization method is introducing a bit level reconstruction/recombination of IPs which have same functionality but different speed and area characteristics for producing more find-grained delay-area optimization.

• Journal of the Korea Fashion and Costume Design Association
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• 제4권3호
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• pp.33-42
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• 2002

The purpose of this study was to find out criteria for classifying fashion brand from consumer point of view in order to develop strategy of fashion brands and to manage brand effectively and systematically, and to suggest theoretical frame for application of these criteria. Survey was used as a research method. Subject were 422 age of 20-30 women living in and near Seoul. Questionnaires was developed to based on 37 classification criteria, and SPSS package program were used to analyze data. The results of this study were as follows: First, factor analysis considering 37 classification criteria identified 8 factors as classification criteria. They were the level of brand form, the level of product concept, the level of management item, the level of brand sales ability, the level of customer management, the level of brand advertizing and awareness, the level of brand value, the level of product lead ability. Second, the most important factor was the level of customer management, but comparatively factor of the level of brand sales ability the level of brand value was less important. Third, consumer cognized difference of criteria for classifying fashion brands. And the level of product lead ability was the most important factor in women's wear category and the level of brand form was in general casual wear category.