• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.318-320
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• 2004

We investigated the basic properties of a superconductive current limiting fuse (SCLF) based on YBCO/Au films. The SCLF consists of meander type YBCO stripes covered with an Au layer for current shunt. The fault current was first limited to a designed value in less than 0.4 msec by resistance development in YBCO/Au upon quenching. This enables the SCLF to transfer small fault power and the suppressed current was sustained for more than 0.5 msec while Au layer melting and arcing. The arcing time was less than 2.5 msec, that is short enough to do self-interruption.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권2호
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• pp.418-430
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• 2014

In this paper, a modelling technique for simulating self-propelled ships in waves is presented. The flow is modelled using a RANS solver coupled with an actuator disk model for the propeller. The motion of the ship is taken into consideration in the definition of the actuator disk region as well as the advance ratio of the propeller. The RPM of the propeller is controlled using a PID-controller with constraints added on the maximum permissible RPM increase rate. Results are presented for a freely surging model in regular waves with different constraints put on the PID-controller. The described method shows promising results and allows for the studying of several factors relating to self-propulsion. However, more validation data is needed to judge the accuracy of the model.

• 전자공학회논문지A
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• 제32A권3호
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• pp.124-133
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• 1995

A theoretical self-consistent thermoelectric model has been developed for optimal thermal design in the self-signal processing infraed detectors. The model is achived by employing the coupled thermoelectric equation which allows which allows the simultaneous investigation of the termal and electrical aspects of device behavior. The thermal limitation of detectivity and responsivity are determined by the enegy gap, carrier concentration, lifetime, and mobility as a function of the temperature. The calculated results indicate that the detectivity is decreased at bias fields above about 50 V/cm, because the performence is limiting by temperature when the bias voltage reached the level associated with Joule heating. It has been also found that the improvement in the mid-band modulation transfer function(MTF) may be restricted by increasing the bias fields. Further, the important paramerers in the thermal optimization of SPIR detector, such as temperature in the device, ambipolar velocity, element thickness and length, are also considered. The analytical study provides a mathematical basis for optimal design of such a photoconductive IR detector and the agreement between the experimental and theoretical results are seen to be good.

• ETRI Journal
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• 제44권2호
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• pp.346-354
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• 2022

The SYN flooding attack is widely used in cyber attacks because it paralyzes the network by causing the system and bandwidth resources to be exhausted. This paper proposed a self-information approach for detecting the SYN flooding attack and provided a detection algorithm with a hierarchical policy on a detection time domain. Compared with other detection methods of entropy measurement, the proposed approach is more efficient in detecting the SYN flooding attack, providing low misjudgment, hierarchical detection policy, and low time complexity. Furthermore, we proposed a detection algorithm with limiting system resources. Thus, the time complexity of our approach is only (log n) with lower time complexity and misjudgment rate than other approaches. Therefore, the approach can detect the denial-of-service/distributed denial-of-service attacks and prevent SYN flooding attacks.

• 한국과학교육학회지
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• 제19권3호
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• pp.471-478
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• 1999

In this study, the relationships among learners' cognitive variables, motivational variables, and conceptual understandings in learning with analogy were investigated. The instruments regarding analogical reasoning ability, field dependence-independence, mental capacity, and logical thinking ability were administered. Some subtests (self-efficacy, expectancy, self-concept of ability, and value) of the Patterns of Adaptive Learning Survey were administered. After students learned with a worksheet that included analogy, a conception test regarding 'stoichiometry that included limiting reagent' was also administered. It was found that learners' conceptual understandings were significantly correlated with the logical thinking ability and the field dependence-independence among the cognitive variables, and the self-efficacy and the self-concept of ability among the motivational variables. The multiple regression analysis of the cognitive variables on conceptual understandings revealed that the logical thinking ability was the most significant predictor. The field dependence-independence also had predictive power. In the analysis of the motivational variables, the self concept of ability was the only significant predictor.

• 한국초전도ㆍ저온공학회논문지
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• 제20권4호
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• pp.55-59
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• 2018

Currently, the development of industry makes needs larger electric supply. Providers must consider the efficiency about losses and reliability of the system. In this case, DC power system can save electrical energy; long-distance transmission line losses. Relevance to switch technology with a voltage-source converter (VSC) in AC-DC conversion system have been researched. But, protection device of DC-link against fault current is still needed to study much. VSC DC power system is vulnerable to DC-cable short-circuit and ground faults, because DC-link has a huge size of capacitor filter which releases extremely large current during DC faults. Furthermore, DC has a fatal flaw that current zero crossing is nonexistence. To interrupt the DC, several methods which make a zero crossing is used; parallel connecting self-excited series LC circuit with main switch, LC circuit with power electronic device called hybrid DC circuit breaker. Meanwhile, self-excited oscillator needs a huge size capacitor that produces big oscillation current which makes zero crossing. This capacitor has a quite effective on the price of DCCB. In this paper, hybrid self-excited type superconducting DCCB which are using AC circuit breaker system is studied by simulation tool PSCAD/EMTDC.

• 의료법학
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• 제21권2호
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• pp.105-162
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• 2020

감염병의 팬데믹 상황 속에서, 국가의 방역 대책은 안보로서의 속성을 지니며, 공중보건과 공공의 이익의 이름으로 개인의 자유에 대한 일정한 제한이 정당화되어왔다. 2020년 3월, 대한민국 국회는 「감염병의 예방 및 관리에 관한 법률」 개정안을 통과시켰으며, 이를 통해 '감염의심자'의 검사 및 격리거부에 대한 처벌의 법적 근거를 신설하고 격리위반과 치료거부의 벌칙을 상향하였다. 본 논문에서는 국가가 개인의 자유를 제한하는 행위의 정당성 판별기준에 대한 자유주의 법철학의 논변과 원리들을 검토하고, 피해자임과 동시에 매개체로서의 속성을 지니는 감염병 환자(patient as victim and vector)에 대한 자유제한원리의 적용은 파인버그(Joel Feinberg)가 제시한 '스스로에 대한 해악(harm to self)'과 '타인에 대한 해악(harm to others)'이 중첩되는 지점에 있음을 개념화하였다. 파인버그가 제기한 자유제한원리(liberty-limiting principle)를 불확실성(uncertainty)을 지니는 팬데믹 상황에 적용하기 위해서는, 해악에서 리스크(risk)로 해악의 원리를 확장시킬 것이 요구된다. 이러한 해악에서 리스크로의 전환은, 불확실한 위기상황 하에서 국가가 사전주의 원칙(precautionary principle)을 통해 개인의 자유를 사전적으로 제한하는 것을 정당화함과 동시에, 충분한 근거 없이 개인의 행위를 처벌의 대상으로 삼는 과잉범죄화(overcriminalization)의 우려를 낳는다. 본 글에서는 리스크를 지닌 개인에 대한 사전적 자유제한을 둘러싼 사전주의의 원칙과 과잉범죄화의 우려 사이에서 균형을 이룰 수 있는 원칙들을 검토한다. 이어서 '타인에 대한 해악' 원칙이 공익과 공중보건 상황에 적용되기 위한 두 번째 확장으로, 인구집단 개념으로의 전환을 다룬다. 팬데믹과 같은 공중보건 위기 상황에서는 '개인'이 아닌 '인구집단'을 하나의 단위로 고려하는 인구집단 접근법(population approach)이 필요하며, 나아가 앞선 두 논의를 결합한 '인구집단에 대한 리스크(risk to population)'가 팬데믹 상황에서 해악의 원리의 중요한 구성요소로 고려되어야 함을 제안한다. 논문의 마지막에서는, 앞서 개념화한 '확장된 해악의 원리' 하에서 개정 「감염병의 예방 및 관리에 관한 법률」의 자유제한이 정당화될 수 있는지 검토한다. 격리위반 처벌조항은 '인구집단에 대한 리스크'에 대한 자유제한에 해당하여, 강제검사 또한 무증상 감염자라는 감염병의 특성에 의거하여 '확장된 해악의 원리'의 차원에서는 정당성이 부정되지 않음을 보일 수 있었다. 그러나 치료거부 처벌조항은 전통적 해악의 원리뿐만 아니라 '인구집단에 대한 리스크'라는 팬데믹의 특성을 고려한 '확장된 해악의 원리' 하에서도 정당화되기 어려우며, 추가적 단서조항을 포함하여야만 정당화 근거를 획득할 수 있을 것임을 논증하였다.

• Tribology and Lubricants
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• 제35권1호
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• pp.65-70
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• 2019

Self-loosening of bolts owing to external forces occurs in several machines that are clamped by bolts and nuts. This study focuses on the self-loosening of the aiming bolt of the head lamp in a vehicle. It is important to prevent the aiming bolt from self-loosening as it has a decisive effect on the angle of the head lamp. A nut clamped with a bolt, known as a retainer, is made of plastic and has a partial screw thread. In addition, a transverse load has a considerable impact on the self-loosening of a bolt. We concentrate on the self-loosening of a bolt by a transverse load. The aim of this study is to define the limits of the external force that loosen the bolt. Based on the above conditions, we derive a theoretical equation and develop a numerical analysis program that can calculate the limiting forces for self-loosening. To verify the developed program, we design a test device that can measure the self-loosening by applying sliding forces to the aiming bolt. Using this method, we can draw the following conclusions. First, the developed testing device is suitable to prove the theory for calculating the self-loosening force. Second, the equation confirms the relationship of bolt self-loosening between resistance torque and shear force. Finally, the equation obtains the minimum value of the resistance torque required to decrease the change in the angle of the head lamp, thereby improving the possibility of increasing the stability of the head lamp.

• 한국임상수의학회지
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• 제20권2호
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• pp.252-254
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• 2003

A 18-month-old, 35.3 kg, intact male Cerman shepherd dog with a history of non-weight bearing lameness in the right hindlimb was referred to Veterinary Teaching Hospital, College of Veterinary Medicine, Kyungpook National University. On physical examination, pain response was elicited. Laboratory abnormalities were not present. Radiographic examination revealed areas of increased opacity in the medullary cavity and accentuation of trabecular patterns of the affected bone. This dog was treated with analgesics and lameness was resolved without pain.

• 전자공학회논문지A
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• 제32A권10호
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• pp.25-34
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• 1995

A new vertical power MOSFET with over-current protection capability is proposed. The MOSFET consists of main power MOSFET cell, sensing MOSFET cell and lateral npn bipolar transistor. The proposed MOSFET may be fabricated by a conventional DMOS process without any additional fabrication step. Overcurrent state is sensed by the newly designed lateral bipolar transistor. Mixed-mode simulations proved that the overcurrent protection is achieved by the proposed MOSFET successfully with a small protection area less than 0.2 % of the total die area.