• 한국인터넷방송통신학회논문지
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• 제14권3호
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• pp.13-19
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• 2014

노트북, 태블릿, 스마트폰 등 모바일 기기들의 성능 향상으로 인하여 임의의 장소에서의 그룹 회의를 진행하는 사람들이 많아지고 있다. 그러나 회의 참석자들이 근거리에 위치하고 있음에도 불구하고 참석자들 간의 데이터의 교환은 셀룰러 망을 이용하여 이루어지고 있다. 이는 불필요하게 셀룰러망에 부하를 가중시키는 원인이 되어 데이터의 송수신 지연을 발생시키고 원활한 회의의 운영 및 일반 모빌 통신 사업자의 통화 품질을 저하시키는 원인이 된다. 이러한 문제를 해결하기 위하여 본 논문에서는 Wi-Fi Direct 기술을 이용하여 근거리 통신기기들 간의 셀룰러 망을 사용하지 않고 회의 참석자들간 직접 통신을 수행할 수 있는 안드로이드 어플리케이션을 개발하고 그 방법에 대하여 소개한다.

• 인문언어
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• 제2권2호
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• pp.301-319
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• 2002

In a recent paper, I have proposed an analysis concerning propositions and 'that'-clauses as a solution to Kripke's puzzle and other similar puzzles, which I now call 'the Indefinite Description Analysis of Belief Ascription Sentences.' I have listed some of the major advantages of this analysis besides its merit as a solution to the puzzles: it is amenable to the direct-reference theory of proper names; it does not nevertheless need to introduce Russellian (singular) propositions or any other new entities. David Lewis has constructed an interesting argument to refute this analysis. His argument seems to show that my analysis has an unwelcome consequence: if someone believes any proposition, then he or she should, ipso facto, believe any necessary (mathematical or logical) proposition (such as the proposition that 1 succeeds 0). In this paper, I argue that Lewis's argument does not pose a real threat to my analysis. All his argument shows is that we should not accept the assumption called 'the equivalence thesis': if two sentences are equivalent, then they express the same proposition. I argue that this thesis is already in trouble for independent reasons. Especially, I argue that if we accept the equivalence thesis then, even without my analysis, we can derive a sentence like 'Fred believes that 1 succeeds 0 and snow is white' from a sentence like 'Fred believes that snow is white.' The consequence mentioned above is not worse than this consequence.

• Journal of Advanced Marine Engineering and Technology
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• 제21권3호
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• pp.284-292
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• 1997

This paper is concerned with position control of direct drive robots. The proposed algorithm consists of the feedback controller and neural networks. Mter the completion of learning, the output of the feedback controller is nearly equal to zero, and the neural networks play an important role in the control system. Therefore, the optimum retuning of control parameters is unnecessary. In other words, the proposed algorithm does not need any knowledge of the con¬trolled system in advance. The effectiveness of the proposed algorithm is demonstrated by the experiment on the position control of a parallelogram link-type direct drive robot.

• Journal of Advanced Marine Engineering and Technology
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• 제21권4호
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• pp.404-413
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• 1997

Direct-drive robots are suitable to position and force control with high accuracy, but it is difficult to design a controller which gives satisfactory perfonnance because of the system's nonlinearity and link-interactions. This paper is concerned with the force control of direct-drive robots. The pro¬posed algorithm consists of feedback controllers and a neural network. Mter the completion of learning, the outputs of feedback controllers are nearly equal to zero, and the neural network con¬troller plays an important role in the control system. Therefore, the optimum adjustment of parameters of feedback controllers is unnecessary. In other words, the proposed algorithm does not need any knowledge of the controlled system in advance. The effectiveness of the proposed algo¬rithm is demonstrated by the experiment on the force control of a parallelogram link-type direct¬drive robot.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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• pp.2542-2548
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• 2009

Direct methylation behaviors of 20 amino acids with tetramethylammonium hydroxide (TMAH) were studied under diluted conditions with silica. Amino acid concentration was controlled by dilution with silica ($SiO_2$) and the molar ratios of amino acid/silica were 0.20, 0.50, and 2.0. The molar ratios of amino acid/TMAH (0.51 - 4.64) also varied. It was found that arginine, asparagine, aspartic acid, cysteine, glutamic acid, and glutamine did not generate any directly methylated pyrolysis products, whereas alanine, glycine, isoleucine, leucine, methionine, phenylanaline, valine, and proline generated all the directly methylated pyrolysis products. Tri- and tetra methylated products of lysine consisted of two types. Histidine and threonine hardly generated the partly methylated products. Mono- and dimethylated products of serine, tryptophan, and tyrosine were not observed. Relative intensities of the methylated products varied with the amino acid concentration, TMAH concentration, and pyrolysis temperature. Direct methylation behaviors of amino acids were explained by the structural characteristics of amino acids.

• East Asian Economic Review
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• 제23권2호
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• pp.111-147
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• 2019

Singapore's inward and outward investments with industrialized countries in both manufacturing and service sectors were skill seeking while outward investments to developing countries were labor seeking. Applying the Knowledge-Capital model, it was found that services Foreign Direct Investment is sensitive to skill differences. A ten-percent decline in skill differences with industrialized countries resulted in a 4.25 percent rise in inbound manufacturing and 1.48 percent rise in inbound services investments. Meanwhile, a ten-percent increase in skill differences with developing countries resulted in a 30 percent rise in outbound manufacturing and 0.38 percent rise in services investments. Furthermore, when services are distinguished by skill-intensity, the impact of relative skill endowments on inbound Foreign Direct Investment in skill-intensive services is significantly different from the impact on other services. However, when services are disaggregated by "proximity" needs, we do not find any significant difference in the impact of relative skill endowments on Foreign Direct Investment.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4297-4303
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• 2011

Under solvent-free conditions, the synthesis of propargylic alcohols by direct addition of terminal alkynes to aldehydes promoted by ZnO as a novel, commercially, and cheap catalyst is described. Furthermore, the catalyst can be reused for several times without any significant loss of its catalytic activity.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.208-210
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• 2007

This paper proposes a novel direct instantaneous pressure control(DIPC) of hydraulic pump system with SR drive. And it has very simple control structure, because it doesn’t use any speed and torque control for adjusting pump pressure. The hysteresis band of pressure and proper switching rules can make the actual pump pressure to be constant with fast dynamic response. Therefore, the proposed DIPC method can control of hydraulic pump pressure steadily with fast dynamic response.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.148-149
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• 2007

In this paper, an advanced torque control scheme of SRM using DITC(Direct Instantaneous Torque Control) and PWM(pulse width modulation) is investigated. The proposed DITC-PWM regulates a duty ratio of the phase switch according to the torque error and simple control rules of DITC without any hysteresis bandwidth. The proposed control method is verified by the simulations and experimental results.

• 한국정보통신학회논문지
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• 제13권12호
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• pp.2618-2624
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• 2009

전기추진선박의 추진시스템에서 중요하게 고려해야 할 사항이 전력변환장치에 의해 전동기에 공급되는 전압 및 전류에 포함되는 고조파 성분을 억제하는 것이다. 근래에 특수선박의 전기추진시스템에서 속도 및 토크제어기법으로 많이 사용하고 있는 벡터제어방식이 많은 제어기와 복잡한 연산을 요구하고 토크의 동적 특성이 전동기의 정수변화에 영향이 큰 단점을 가지고 있어서 대안으로 제시되고 있는 제어기법 중에 하나가 직접토크제어방식이다. 하지만 직접토크제어방식은 영벡터를 인가하지 않으므로 토크리플이 심하여 공급 전류파형에 고조파 성분이 포함되는 단점을 가지고 있으므로 이를 해결해야 한다. 본 논문에서는 유도전동기를 추진기로 채용하고 있는 LNG 선박의 전기추진시스템에서 직접토크제어방식을 사용하는 경우에 고조파 발생을 저감하기 위한 제어방식을 제시한다. 새로운 직접토크제어방식은 샘플링 주파수의 변화없이 복잡한 제어기를 사용하지 않고 인버터 스위칭 주파수를 일정하게 유지한 채 개선된 공간벡터 변조법에 의해 인버터를 제어하는 방식이다. 제안된 방식의 유효성은 추진기에 공급되는 전류파형에 포함된 고조파 성분의 분석과 속도제어 특성을 통해 입증한다.