• Journal of Chest Surgery
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• 제6권2호
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• pp.219-224
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• 1973

82 cases of esophageal stenosis due to lye solution in our hospital, which is surgicallly treated with retrosternal esophagoplasty were reported. female was 2 times more then male and average age is 30 years old. Dyphagia and precordial pain were chief complaint. In this technique, jejunum, right and left colon were substituted for constricted esophagus. Postoperative complication rate 14.6%, mortality rate due to other complication were 21.9% but had not seen in this operative technique.

• Structural Engineering and Mechanics
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• 제24권5호
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• pp.601-620
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• 2006

The paper presents an effective stiffness model for deformational analysis of reinforced concrete cracked members in bending throughout the short-term loading up to the near failure. The method generally involves the analytical derivation of an effective moment of inertia based on the smeared crack technique. The method, in a simplified way, enables us to take into account the non linear properties of concrete, the effects of cracking and tension stiffening. A statistical analysis has shown that proposed technique is of adequate accuracy of calculated and experimental deflections data provided for beams with small, average and normal reinforcement ratios.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.40-52
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• 1998

Among the non-traditional machining methods, Abrasive waterjet machining process shows big promise in drilling difficult-to-machine materials due to its numerous advantages such as absence of heat affect zone and thermal distortion. Acoustic emission signal technique is used to understand about material removal mechanisms during abrasive waterjet drilling process. More information about the drilling process is derived through frequency decomposition of auto regressive moving average modeling representing acoustic emission signals.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.233-236
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• 2001

Orthogonal freqency division multiplexing (OFDM) is an attractive technique for achieving high-bit-rate wireless data transmission. However, the potentially large peak-to-average power ratio (PAPR) has limited its application; An OFDM signal with the large PAPR can cause power degradation (In-band distortion) and spectral spreading (Out-of-band distortion) by being clipped passing through a power amplifier. Thus, we propose the combining algorithm of Hadamard transform and phase shift, which is ascribed to the relation between the correlation of the IFFT input sequence function and PAPR. Extensive computer simulations show that the combining algorithm is an effective technique to reduce PAPR.

• The Journal of Advanced Prosthodontics
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• 제9권1호
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• pp.1-13
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• 2017

PURPOSE. The purpose of this study was to compare the fit of cast gold crowns fabricated from the conventional and the digital impression technique. MATERIALS AND METHODS. Artificial tooth in a master model and abutment teeth in ten patients were restored with cast gold crowns fabricated from the digital and the conventional impression technique. The forty silicone replicas were cut in three sections; each section was evaluated in nine points. The measurement was carried out by using a measuring microscope and I-Soultion. Data from the silicone replica were analyzed and all tests were performed with ${\alpha}$-level of 0.05. RESULTS. 1. The average gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. 2. In marginal and internal axial gap of cast gold crowns, no statistical differences were found between the two impression techniques. 3. The internal occlusal gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. CONCLUSION. Both prostheses presented clinically acceptable results with comparing the fit. The prostheses fabricated from the digital impression technique showed more gaps, in respect of occlusal surface.

• Journal of electromagnetic engineering and science
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• 제7권1호
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• pp.1-6
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• 2007

Recently, Mc(Multi-code) modulation/demodulation(modem) technique has been explored for high speed data transmission in wireless environment. The conventional Mc modem generates some side effects such as allocating Walsh codes, which motivates to propose a novel Mc modem method with sub-code. Our proposed system should expanded the size of sub-code to provide high-rate data transmission, which also affect adversely to the performance of the system with high PAPR(Peak to Average Power Ratio). Thus, in this paper, we propose a novel pre-coded Multi-Dimensional HCOC(High Capacity Orthogonal Code) Mc modem technique to reduce the high PAPR, which enables the performance improvement. This proposed system can be easily designed by concatenating HCOC Mc modem with the generic Mc modem. The pre-coding technique that is used in this paper is CAC(Constant Amplitude Coding), that helps the system maintain the constant transmission power and reduce the maximum transmission power.

• 한국환경보건학회지
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• 제26권3호
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• pp.50-54
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• 2000

Ventilation rates can be measured directly by a tracer decay method, although little is known of the effects of different sampling intervals on decay rte calculations. This study determined variations in decay rates calculated by three techniques using residential ozone decay data. The calculation techniques were a regression technique, decay techniques using half-life and average-life, and finite difference techniques using two different time intervals. Variation associated with regression technique calculations for residential ozone decay rates based on data from both sample intervals were within 10% (2.81$\pm$1.88 hr-1). However, both half-life and finite difference technique calculations using a shorter-time interval were significantly different from those obtained with the regression technique(p<0.05). Therefore, the use of short sampling intervals in tracer decay may cause significant error in decay rate calculations.

• KSTLE International Journal
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• 제6권1호
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• pp.21-27
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• 2005

A technique for a wear volume calculation is improved and verified in this research. The wear profile data measured by a surface roughness tester is used. The present technique uses a data flattening, the FFT and the windowing procedure, which is used for a general signal processing. The measured value of an average roughness of an unworn surfnce is used for the baseline of the integration for the volume calculation. The improvements from the previous technique are the procedures of the data flattening and the determination of a baseline. It is found that the flattening procedure efnciently manipulates the raw data when the levels of it are not horizontal, which enables us to calculate the volume reasonably well and readily. By comparing it with the weight loss method by using artificial dents, the present method reveals more volume by aroung 3~10%. It is attributed to the protruded region of the specimen and the inaccuracy and data averaging during the weght loss measurement. From a thorough investigation, it is concluded that the present technique can provide an accurate wear volume.

• 수산해양교육연구
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• 제17권1호
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• pp.67-75
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• 2005

Mobile devices compared with personal computers on the desktop have low bandwidths, small screens, and relatively slow speeds. These systems have practical problems with information searches in a web environment. Information searching of various web contents on the small size screen has especially severe limitations. We propose a filtering technique of web contents which can overcome the limitations of small size screens and meet the user requirements in a PDA environment. For these constructions, we first divide the screen into segment blocks and then extract content blocks according to the user requirements, so that only filtered web contents will be shown. The performance evaluation of the proposed technique saves an average time of about 30% by displaying only the extracted information instead of the whole web page.

• 한국통신학회논문지
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• 제28권2C호
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• pp.201-208
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• 2003

에러 은폐기법은 네트워크를 통한 영상회의 등 실시간 전송을 필요로 하는 응용분야에서 매우 유용한 기법이다. 본 논문에서는 불연속에 민감한 시각 특성을 고려하여 블록 경계의 차를 최소화하는 에러 은폐기법을 제안한다. 손실 블록에 대한 에러 은폐는 그래디언트 차에 기반을 둔 확장된 매칭 기법을 이용하여 달성된다. 제안된 기법은 실험 영상에 대한 컴퓨터 모의 실험을 통해 기존의 기법에 비해 평균 약 1.3㏈ 의 화질의 향상을 가져왔다.