• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3181-3183
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• 1999

A CMOS two-stage oscillator applicable to requiring in- and quadrature-phase components such as RF and data retiming applications are presented using phase-look-ahead technique. This paper clearly describes the operation principle of the presented two-stage oscillator and the principle can be also applicable to the high speed high speed divide-by-two is usually used for prescaler of the frequency synthesizer. Also, the sucessful oscillation of the proposed oscillator using PLA is confirmed through the experiment. The test vehicle is designed using 0.8 ${\mu}m$ N-well CMOS process and it has a maximum 914MHz oscillation showing -75dBclHz phase noise at 100kHz offset with single 2V supply.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.2
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• pp.49-55
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• 2003

This paper presents a novel three-phase current-fed Pulse Width Modulation converter with switched capacitor type resonant DC link commutation circuit operating PWM pattern strategy under a design consideration of low-pass filter, which can operate on the basis of the principle of zero current soft switching commutation. In the first place, the steady state operating principle of this converter with a new resonant DC link snubber circuit is described in connection with the equivalent operation circuit, together with the practical design procedure of the switched-capacitor type resonant DC link circuit is discussed from a theoretical viewpoint on the basis of a design example for high-power applications. The actively delayed time correction method to compensate distorted currents due to a relatively long resonant commutation time is newly implemented in the open loop control scheme so as to acquire the new optimum PWM pattern. Finally, the experiment of set-up in laboratory system of this converter is concretely demonstrated herein to confirm a zero current soft-switching commutation of this converter. The comparative evaluations between current-fed hard switching PWM and soft-switching PWM converters are carried out from a viewpoint of their PWM converter characteristics.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.4
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• pp.267-272
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• 2013

As an important operation with many applications such as data cleaning and duplicate detection, the similarity join is a challenging issue, which finds all pairs of records whose similarities are above a given threshold in a dataset. We propose a new algorithm that uses the prefix filtering principle as strong constraints on generation of candidate pairs for fast similarity joins. The candidate pair is generated only when the current prefix token of a probing record shares one prefix token of an indexing record within the constrained prefix tokens by the principle. This generation method needs not to compute an upper bound of the overlap between two records, which results in reduction of execution time. Experimental results show that our algorithm significantly outperforms the previous prefix filtering-based algorithms on real datasets.

• Archives of Plastic Surgery
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• v.35 no.2
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• pp.165-168
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• 2008

Purpose: The dog bite injury is expected to increase as westernizing lifestyle and the number of pet raisers increase. The bite injuries may cause serious sequelae. The purpose of this study is to contributes to establish a suitable management and treatment principle for domestic situation with a clinical analysis data of the dog bite injuries. Methods: We reviewed the hospital records of 76 patients with dog bite injuries who were treated in the emergency unit or out patient department of our hospital from January 2000 to May 2006. Results: The majority of patients were children less than 10 years of age, 21 case(27.6%). Injuries occurred most often in May and 14 patients(18.4%) were bitten by the kinds of Cockerspaniel. By Lackmann's classification, 36 patients(47.4%) had Stage I injuries, 27 patients (35.5%) Stage II, 11 patients(14.5%) Stage III and 2 patients(2.6%) Stage IVa. The most frequent injury site was the head and neck area with 55 cases(72.4%). Also, 58 cases(76.3%) were received the initial treatment within 30 minutes after being bitten and the most of case except emergency operation repaired within 3 days.Conclusion: The dog bite injuries increased by more than 20% every year over the study period and it says that it may continue to increase more in the future. However, There are little report or literature for suitable management and treatment principle for domestic situation. The authors think this clinical analysis data and treatment experience can be useful for establishing a suitable treatment principle for domestic situation.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.03a
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• pp.201-201
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• 1999

감성(sensitibility)은 반사적이며 직관적으로 발생하고, 인위적인 조정이 불가능하며 명확한 표현이 어렵고 모호하다고 한다. 또 감정(emotion)이 주어진 대상에 따라 동일한 반응을 보이는 공통성을 갖지만, 감성은 동일한 대상에도 개인에 따라 다양한 반응을 보이며, 시간과 환경에 따라 변한다고 본다. 이는 반응 형성의 두 가지 요소인 외부의 자극이나 대상과 반응하는 주체의 양자에서, 감정이 감성에 비해 외부의 자극이나 대상의 영향을 더 받고, 감성은 상대적으로 외부 상황보다는 반응 주체의 다양한 내부 상황에 따라 결정된다는 것을 의미할 수 있다. 이러한 감성의 특징들은 Freud가 말한 무의식의 특징과 비슷한 점이 많다. 따라서 무의식의 작용양상을 살펴보는 것이 감성의 연구에 도움이 될 수 있다고 생각한다. 무의식이란 우리의 마음에 항상 작용하고 있지만, 일상적인 상태에서는 분명하게 알아 볼수가 없고 확실하게 드러나지도 않는 어떤 힘을 말한다. 이는 개인의 다양한 과거 경험이 포함되어 있어서 사람에 따라 각기 다르게 나타나게 된다. 우리가 항상 경험하고 있는 의식은 확실하게 서로 구분되는 대상과 확인율(the principle of identity), 구분논리(bivalent logic), 모순율(the principle of formal contradiction), 상반율(the principle of incompatibility), 가감율(the operation of substraction)을 수용하여 작용한다. 무의식은 의식활동의 이러한 명료함과 정연함을 벗어나 활동한다. 대상간의 구분이 모호해지고 정연한 논리가 흐트러진다. 일상에서는 꿈의 내용과 어린이의 생각, 감정에 치우칠 때 무의식의 특징이 나타난다. Freud는 꿈을 관찰하여 무의식의 작용양상을 다음과 같이 설명하였다. 서로 상반되는 것들이 다음과 같이 설명하였다. 서로 상반되는 것들이 부딛힘이 없이 공존하고 일상의 논리가 무시된다. 부정, 의심이 없고 확실한 것이 없다. 한 대상에 가졌던 생각이 다른 대상에 옮겨간다(displacement). 한 대상이 여러 대상이 갖고 있는 의미를 함축하고 있다(condensation). 시각적인 순서가 무시된다. 마음속의 생각과 외부의 실제적인 일을 구분하지 못한다. 시간 상의 순서가 있다가 없다가 한다. 차례로 일어나야 할 일이 동시에 한꺼번에 일어난다. 대상들이 서로 비슷해지고 동시에 있을 수 없는 대상들이 함께 나타난다. 사고의 정상적인 구조가 와해된다. Matte-Blance는 무의식에서는 여러 독립된 대상들간의 구분을 없애며, 주체와 객체를 하나로 보려는 대칭화(symmetrization)의 경향이 있기 때문에 이런 변화가 생긴다고 하였다. 또 대칭화가 진행되면 무한대의 느낌을 갖게 되어, 전지(moniscience), 전능(omnipotence), 무력감(impotence), 이상화(idealization)가 나타난다. 그러나 무의식에 대칭화만 있는 것은 아니며, 의식의 사고양식인 비대칭도 어느 정도 나타나며, 대칭화의 정도에 따라, 대상들이 잘 구분되어 있는 단계, 의식수준의 감정단계, 집단 내에서의 대칭화 단계, 집단간에서의 대칭화 단계, 구분이 없어지는 단계로 구분하였다.

• Journal of Educational Research in Mathematics
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• v.27 no.2
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• pp.249-267
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• 2017

The unit of multiplication in the mathematics textbook for third graders deals with two-digit number multiplied by one-digit number. Students tend to perform multiplication without necessarily understanding the principle behind the calculation. Against this background, we designed the unit in a way for students to explore the principle of multiplication with cuisenaire rods and array models. The results of this study showed that most students were able to represent the process of multiplication with both cuisenaire rods and array models and to connect such a process with multiplicative expressions. More importantly, the associative property of multiplication and the distributive property of multiplication over addition were meaningfully used in the process of writing expressions. To be sure, some students at first had difficulties in representing the process of multiplication but overcame such difficulties through the whole-class discussion. This study is expected to suggest implications for how to teach multiplication on the basis of the properties of the operation with appropriate instructional tools.

• Journal of the Korean earth science society
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• v.28 no.5
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• pp.572-584
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• 2007

The quantification of ammonia concentrations has received a lot of scientific attention. Numerous devices for the quantification of $NH_3$ in the ambient air have been developed to provide more technical possibilities for research in abating $NH_3$ emission from various source processes. For the proper quantification of $NH_3$, a number of sampling methods have been discussed by grouping them into different categories based on the principle of functioning. In general, active samplers employ pumps to draw air in, while passive samplers are exposed to air over a certain period of time to obtain integrated signature of $NH_3$. In case of the former, impingers and absorption flasks can be employed simultaneously with suitable absorbents to capture $NH_3$ passing through them. The methods of analysis include both in-situ and laboratory determination. In the laboratory, colorimetric or ion chromatographic methods are generally used for its quantification. In the field, a number of real time analyzers have been proven to be useful. These real time analyzers can be grouped according to their principle of operation. These analyzers may use the principle of spectroscopy (e.g. DOAS), photoacousticics (e.g. photoacoustic monitor) or Chemiluminescence ($NO_x$ analyzer). The automated annular denuder sampling system with on-line analyzer is also suitable for continuous monitoring of ammonia in air.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.2
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• pp.110-119
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• 1999

The principle of guided tissue regeneration (GTR), as applied to bone healing, is based on the prevention of connective tissue from entering the bony defect during the healing phase. This allows the slower bone producing cells to migrate into and reproduce bone within the defect. The principle of guided tissue regeneration has demonstrated a level of success in regenerating bone defect. Several types of membrane barrier, each one with distinct properties, have been utilized to apply this principle in bone regeneration. The purpose of this study is to introduce and discuss the attributes of rubber dam as a barrier membrane and evaluate whether improved bone regeneration can be achieved by GTR using rubber dam. In the 15 New Zealand white rabbits, full-thickness bone defects on three sites of each rabbit calvaria were made. Non membrane group served as a control and experimental group 1 was covered with rubber dam and group 2 covered with Gore-Tex$^{TM}$ membrane. Macroscopic, radiographic, microscopic examinations were made serially on 1, 2, 3, 6, 12 weeks after operation. The results were as follows: 1. Macroscopically, the control site was collapsed and filled with connective tissue throughout the experimental period. But the defects of experimental groups 1 and 2 were filled with bone-like mass and showed the hard consistency on palpation. 2. Radiographically, the early new bone formation appeared similarly from the host bone in groups 1 and 2. 3. Microscopically, there were much connective tissue at the central part of control site but the defect of group 1 and 2 was filled with the mature bony trabeculae on the 12th week. This results suggest that rubber dam can be effectively used as a barrier membrane for guided bone regeneration.

• Journal of Korean Society for Quality Management
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• v.10 no.2
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• pp.2-9
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• 1982

In principle the methods of increasing the reliability of complex system can be classified into the following four basic methods: (1) using the stand-by redundancy; (2) decreasing the failure rate of the system; (3) decreasing the time of continuous operation; (4) decreasing the mean repair time. Among the above four methods, it is generally known that the method of stand-by redundancy is the most effective general, to increase the reliability of systems. Therefor this paper aims to compare the gain in reliability which is achieved by applying stand-by redundancy with other methods, and to show the characteristics of each method From the comparison of the methods of increasing reliability, the following important facts are found: When the method of stand-by redundancy is used to increase the reliability of complex systems intended for long-term operation, a hight multiplicity of stand-by redundancy is required. Thus an increase of the reliability of complex system by applying stand-by redandancy is realized at the expense of characteristics such as weight, size, cost, increased complexity of operation conditions. And this property restricts its use in systems which are critical with respect to weight, size, cost or operation conditions. The method of stand-by redundancy is the most effective when this method is used to increase the reliability of complex systems intended for short-term operation, and the method of decreasing failure rate is the most effective when it is used to increase the reliability of systems intended for long-term use. The methods of increasing reliability discussed in this paper make it possible to make highly reliable systems. But it is not possible to make a highly reliable system using a single method of increasing reliability, even if it is the most effective one. Therefore it is recommended to use all or a majority of the above four methods by choosing it in accordance with the properties of the system under construction.

• The Journal of Korean Institute of Information Technology
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• v.16 no.11
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• pp.23-34
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• 2018

This paper presents the high efficiency and high power-factor power supply for LED lighting equipment. The proposed power supply is the single-stage power structure consisted of the full-bridge diode rectifier and flyback converter, and thus the power-factor correction and output voltage regulation are performed simultaneously using only one controller IC and one power semiconductor switch. Furthermore, the proposed power supply reduces the voltage stress and switching loss of main switch using the regenerative snubber, and it improves the system efficiency using the synchronous rectifier. The applied synchronous rectifier is the new voltage-driven type and its operation and construction are simple. In this paper, the operation principle of proposed power supply is explained through the operation analyses of its power-factor correction and main power conversion parts and the operation of synchronous rectifier is described, briefly. Also, a design example of the power circuit of 40W-class prototype is shown and the operation characteristics of proposed power supply are validated through the experimental results of the implemented prototype by the designed circuit parameter.