• 대한치과의사협회지
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• 제22권12호통권187호
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• pp.1067-1073
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• 1984

In the treatment of functional orthodontic problems, timing is not an issue. All orthodontists start as soon as the condition is recognized. However, there is an active dialogue concerning treatment timing for structure problems. The major points in contention center around the operator's ability is to control the growth of the facial bones and to maintain post-treatment tooth position through the maturation period (especially when this position was gained by techniques involving arch expansion or distal driving of posterior segments). Factors taken into account to determine the best time of orthodontic treatment include diagnosis, interception, growth rate, patient cooperation, eruptive state and treatment period. With those exceptions of all functional problems, mild dental discrepancies and skeletal deficiencies with a predictably excellent growth potential (early treatment), the period immediately following the eruption of the permanent second molars is the period during which most orthodontic treatment should be initiated. At this time the full volume of tooth substances is present, the individual growth pattern in well established, there are sufficient teeth to receive nearly any type of appliances and the patient can easily tolerate the wearing of appliances.

• 한국자동차공학회논문집
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• 제7권5호
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• pp.9-15
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• 1999

A digital CDI(Capacitive Discharge Ignition) system on small two stroke motorcycle engine was developed in this paper, This CDI system with microprocessor as its main part has more flexible spark timing than the conventional CDI system because of its programmable characteristics. The principle of this digital CDI system and the design methods of hardware and software were presented in this paper, Two stroke small engine was tested to investigate the performance of digital CDI system And also this system was investigated to optimize the engine performance. Also comparison between conventional CDI can provide better spark timing variation than the conventional system. The part and full load test results show that the engine power was increased about 10-20% and fuel consumption was decreased about 10-20% simultaneously. Furthermore, this digital CDI system has simple structure, low cost and very little modification are required. It is a promising technology to substitute for the widely used conventional CDI system.

• 한국정보처리학회논문지
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• 제6권6호
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• pp.1635-1645
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• 1999

본 논문에서는 아키텍춰-수준에서 타이밍 최적화를 효과적으로 수행하기 위한 지능적인 재합성 기술에 대하여 연구하였다. 구체적으로는 아키텍춰-수준에서 계층 구조를 가지는 회로 구조에 기존의 조합적 타이밍최적화 방법을 적용함으로써 발생하는 문제점을 해소시킬 수 있는 방법을 제시하였다. 접근 방법은 우선 설계자가 설계한 계층 구조를 유지시키는 방법으로 기존의 retiming 방법과 peripheral retiming 방법을 응용하여 서브컴퍼넌트 내 조합논리회로 부분을 확대하는 방법을 이용한다. 이와 같은 방법이 좋은 결과를 가져오지 못할 때 다른 접근 방법으로서 기존의 서브컴퍼넌트들로 이루어지는 경제를 새로운 경계를 가지는 새로운 서브컴퍼넌트들로 변형시켜 서브컴퍼넌트들 각각의 독립적인 타이밍최적화로 전체 회로에 대한 타이밍최적화를 이끌어 낼 수 있도록 한다. 본 논문은 아키텍춰-수준에서 계층적 구조를 가지는 회로에 대한 새로운 접근을 시도하고 있는데, 회로가 크고 복잡해짐에 따라 설계자가 실제 회로를 대부분 서브컴퍼넌트화하여 계층적 구조를 가지도록 설계하는 것이 일반적인 상황에서 이의 효능성을 실험적으로 입증할 수 있다.

• 음성과학
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• 제11권3호
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• pp.23-36
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• 2004

Many languages show reverse durational variation between preceding vowel and following voiced/voiceless (lax/tense) consonants. This study investigated the likely effects of phoneme type (tense vs. lax) on the timing structure (duration of syllable, word, phrase and sentence) of Korean. Three rates of speech (fast, normal, slow) applied to stimuli with the target word /a-Ca/ where /C/ is one of /p, p', $p^h$/. The type (tense/lax) of /C/ caused marked inverse durational variations in the two syllables /a/ and /Ca/ and highly different durational ratios between them. Words with /p', $p^h$/ were significantly longer than that with /p/, which contrasts with many other languages where such pairs of words have a similar duration. The differentials between words remained up to the phrase and sentence level, but in general the higher linguistic units did not statistically differ within each level. Thus, the phrase is suggested as a compensatory unit of phoneme type effects in Korean. Different rates did not affect the general tendency. Distribution of time variations (from normal to fast and slow) to each syllable (/a/ and /Ca/) was also observed.

• 한국공작기계학회논문집
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• 제16권2호
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• pp.112-119
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• 2007

In order to predict vibration trends occurred during vehicle drive, acceleration data was processed by using data processing algorithm with moving average and Hilbert transform. Specific mode constants of acceleration were obtained under various disturbance. Vehicle velocity, road condition, property of pointing structure were considered as factors which make change of vibration trend in vehicle dynamics. Results of signal processing were compared and analysed. Advanced performance of the timing selection algorithm from this study was verified by using simple equipment comparing with the deflection measurement laser system(Muzzle Reference System).

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.159-160
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• 2006

We present a multiuser synchronization scheme for OFDMA uplink systems. First a new preamble structure is proposed by which timing and frequency offsets estimation is developed. Based on proposed structure a new joint synchronization scheme is presented and the simulation results show that the performance of this scheme don't suffer from the number of users.

• Journal of Positioning, Navigation, and Timing
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• 제3권3호
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• pp.91-97
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• 2014

A direct RF sampling method refers to a technique that directly converts a passband signal to an intermediate band or a baseband without using a mixer. This method is less complicated than an existing RF receiver because a mixer is not used. It uses digital processing after sampling, and thus can flexibly process signals in a number of bands using software. In this process, it is important to select an appropriate sampling frequency so that a number of signals can be converted to an intermediate band that is easy to process. In this study, going beyond previously studied direct RF sampling frequency selection methods, conditions that need to be additionally considered during receiver design were examined, and the structure of a direct RF sampling receiver that satisfies these conditions was suggested.

• 한국전자파학회논문지
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• 제20권5호
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• pp.493-502
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• 2009

본 논문에서는 DS-UWB 시스템에 사용되는 송신 필터에 따른 초기 동기 획득 성능을 모의 실험을 통해 비교하고, 칩 레이트가 1.32 Gchip/s인 DS-UWB 디지털 송신기에서 interpolation factor가 4인 제곱근 코사인 필터를 적용한 경우와 구형 필터를 적용한 경우 DS-UWB 수신기의 초기 동기 획득 성능은 AWGN 채널 환경뿐만 아니라 CM1/CM3 채널 환경하에서도 비슷한 성능을 냄을 실험을 통해 살펴 본다. 또한, 55 MHz의 시스템 클럭으로 동작하는 24 병렬 처리 상관 연산기 및 동기 획득기 구조에 대해 설명하고 초기 동기 획득 방법을 기술한다. 본 논문에서는 DS-UWB 시스템 설계시 구형 송신 필터를 사용하여 1.32 Gsample/s D/A 변환기 및 A/D 변환기를 적용할 수 있게 함으로써 DS-UWB 칩셋 개발시 현실적으로 고려할 수 있는 솔루션을 제시한다.

• 대한전자공학회논문지SD
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• 제47권8호
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• pp.47-55
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• 2010

본 논문에서는 고해상도 저전력 SAR 타입 ADC(아날로그 디지털 변환기)의 면적을 획기적으로 줄이기 위해서 역 다중화기 (Demultiplexer)와 카운터 (Counter)를 이용하는 타이밍 레지스터 (Timing register) 구조를 제안하였다. 전통적으로 사용되는 쉬프트 레지스터에 기반을 둔 타이밍 레지스터 구조는 해상도가 증가될수록 면적이 급격하게 증가하고, 또한 잡음의 원인이 되는 디지털 소비 전력도 증가되는 반면, 제안하는 구조는 해상도 증가에 따른 에러 보정 회로의 면적과 소비 전력 증가를 줄일 수 있다. 0.18 um CMOS 공정을 이용하여 제작하였으며, 제안한 타이밍 레지스터 구조를 이용하여, 기존 구조 대비 5.4배의 면적 감소와 디지털 전력 최소화의 효과를 얻을 수 있었다. 설계한 12 비트 SAR ADC는 11 비트의 유효 비트 (ENOB), 2 mW (기준전압 생성 블록 포함)의 소비전력과 1 MSPS의 변환 속도를 보였으며, 레이아웃 면적은 $1mm{\times}1mm$ 이었다.

• 한국시뮬레이션학회논문지
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• 제3권2호
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• pp.1-13
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• 1994

Deep reasoning procedures are model-based, inferring single or multiple causes and/or timing relations from the knowledge of behavior of component models and their causal structure. The overall goal of this paper is to develop an automated deep reasoning methodology that exploits deep knowledge of structure and behavior of a system. We have proceeded by building a software environment that uses such knowledge to reason from advanced symbolic simulation techniques introduced by Chi and Zeigler. Such reasoning system has been implemented and tested on several examples in the domain of performance evaluation, and event-based control.