• 대한조선학회지
• /
• 제26권2호
• /
• pp.25-31
• /
• 1989

정규칙파 중에서의 이차원 주상체의 대진폭 운동이 시간영역 수치계산법에 의해 다루어졌다. 물체표면 경계조건을 각 순간의 실제 물체표면에서 적용하므로 대진폭 운동에서 고려되어야 하는 물체 위치변화 및 형상변화 등에 의한 비선형효과가 고려되고 있으며, 자유표면에서의 비선형효과는 고려되지 않는다. 단순강제동요 및 자유동요문제에 적용된 바 있는 물체 표면 소오스 분포와 자유표면 스펙트럴 표현방법이 입사파의 강제력을 포함하도록 확장 적용되었고 물체의 운동응답은 시간적분법에 의해 계산되었다. 잠수 및 부유주상체의 대진폭 운동이 시간영역에서 직접 시뮬레이션되어 비선형 효과들이 보여지고 있으며, 대진폭 운동시 파강제력에 영향을 미치는 비선형효과가 고찰되어, 물체와 유체입자의 상대운동이 수평 및 수직방향 시간평균력들에 상당한 영향을 미침이 보여지고 있다.

• 한국농공학회지
• /
• 제32권3호
• /
• pp.116-129
• /
• 1990

A rational management of water resources in estuary reservoirs necessiates the prediction of water quality. In this study, a multiple box model for the water quality prediction was developed as a tool for the purpose of examining an adequate way to improve and maintain the water quality. Some submodels that are suitable for simulating the mixing behavior of pollutant materials in a lake were considered in this model. The model was appiled for predicting water qualities of Haenam Esturay Reservoir. The result from this study can be summarized as follows : 1.A water quality simulation model that can predict the 10-day mean value of water qualities was developed by adding some submodels that simulate the concentrations of chlorophyll-a, BOD, T-P and T-N to the existing Multiple Box Model representing the mixing and circulating of materials by the hydarulic action. 2.As input data for the model developed, the climatic data including precipitation, solar radiation, temperature, cloudness, wind speed and relative humidity, and the water buget records including the pumping discharge and the releasing discharge by drainage gate were ollected. The hydrologic data for the inflow discharge from the watershed was obtained by simulation with the aid of USDAUL-74/SNUA watershed model. Also the water quality data were measured at streams and the reservoir. 3.As a result of calibration and verification test by using four comonents of water quality such as Chlorophyll-a, BOD, T-P and T-N, it was found that the correlation coefficeints between the observed and the simulated water qualities showed greater than 0.6, therefore the capability of the model to simulate the water quality was proved. 4.The result based on the model application showed that the water quality of the Haenam Estuary Reservoir varies seasonally with the harmonic trend, however the water quality is good in winter and get worse in summer. Also it may be concluded that the current grarde of water quality in the Heanam Esutary Reservoir is ranked as grade 4 suitable only for the agricultutal use.

• 한국농공학회지
• /
• 제35권3호
• /
• pp.100-116
• /
• 1993

It is experienced fact that unreasonable design criterion and unsitable operation management for the agricultural structures including reservoirs based on short terms data of monthly flows have been brought about not only loss of lives, but also enormous property damage. For the solution of this point at issue, this study was conducted to simulate long series of synthetic monthly flows by multi-season first order Markov model with selection of best fitting frequency distribution and to make a comparison of statistical parameters between observed and synthetic flows of six watersheds in Yeong San and Seom Jin river systems. The results obtained through this study can be summarized as follows. 1.Both Gamma and two parameter lognormal distribution were found to be suitable ones for monthly flows in all watersheds by Kolmogorov-Smirnov test while those distributions were judged to be unfitness in Nam Pyeong of Yeong San and Song Jeong and Ab Rog watersheds of Seom Jin river systems in the $\chi$$^2$ goodness of fit test. 2.Most of the arithmetic mean values for synthetic monthly flows simulated by Gamma distribution are much closer to the results of the observed data than those of two parameter lognomal distribution in the applied watersheds. 3.Fluctuation for the coefficient of variation derived by Gamma distribution was shown in general as better agreement with the results of the observed data than that of two parameter lognormal distribution in the applied watersheds both in Yeong San and Seom Jin river systems. Especially, coefficients of variation calculated by Gamma distribution are seemed to be much closer to those of the observed data during July and August. 4.It can be concluded that synthetic monthly flows simulated by Gamma distribution are seemed to be much closer to the observed data than those by two parameter lognormal distribution in the applied watersheds. 5.It is to be desired that multi-season first order Markov model based on Gamma distribution which is confirmed as a good fitting one in this study would be compared with Harmonic synthetic model as a continuation follows.

• Ocean and Polar Research
• /
• 제25권1호
• /
• pp.89-106
• /
• 2003

Analyses of tidal observations and a numerical model of the $M_2$ and $M_4$ tides in the Uldolmok waterway located at the southwestern tip of the Korean Peninsula are described. This waterway is well known fer its strong tidal flows of up to more than 10 knots at the narrowest part of the channel. Harmonic analysis of the observed water level at five tidal stations reveals dramatic changes in the amplitude and phase of the shallow water constituents at the station near the narrowest part, while survey results show a decreasing trend in local mean sea levels toward the narrow section. It was also observed that the amplitudes of semi-diurnal constituents, $M_2$ and $S_2$ are diminishing toward the narrowest part of the waterway. Two-dimensional numerical modeling shows that the $M_2$ energy flux is dominated by the component coming from the eastern boundary. The $M_2$ energy is inward from both open boundaries and is transported toward the narrow region of the channel, where it is frictionally dissipated or transferred to other constituents due to a strong non-linear advection effect. It is also shown that the $M_4$ generation is strong around the narrow region, and the abrupt decrease in the M4 amplitude in the region is due to a cancellation of the locally generated M4 with the component propagated from open boundaries. The superposition of both propagated and generated M4 contributions also explains the discontinuity of the M4 phase lag in the region. The tide-induced residual sea level change and the regeneration effect of the $M_2$ tide through interaction with $M_4$ are also examined.

• 한국산림과학회지
• /
• 제107권2호
• /
• pp.158-165
• /
• 2018

산지하천의 평균유속을 정확하게 추정하는 것은 하천의 수리적 흐름을 이해하고, 사방댐과 같은 사방구조물 최적 설계를 위해 중요하다. 산지하천의 평균 유속에 대한 연구는 부족한 실정이나 최근에는 상대적으로 자료 확보가 용이한 유량 자료를 이용하여 유량과 평균유속의 관계를 파악하는 연구들이 많이 진행되고 있다. 이 연구에서는 8개소의 서로 다른 산지소하천에서 조사된 87회의 유량과 평균 유속 자료를 분석하였다. 산지하천의 유량과 평균유속을 측정하기 위해 salt-dilution 방법을 사용하였으며, 평균유속은 도달 시간의 조화 평균을 적용하여 구하였다. 하천의 거칠기 높이를 이용하여 유량과 유속과의 무차원 관계식을 도출하였다. 거칠기 높이는 하상재료의 $D_{50}$, $D_{84}$와 하상변위의 ${\sigma}_{pro}$, $IPR_{90}$를 이용하였으며, ${\sigma}_{pro}$와 $IPR_{90}$의 정확성이 더 높게 나타났다. 일반적으로 유량과 평균 유속은 지수함수 관계를 보였다.

• 물과 미래
• /
• 제15권2호
• /
• pp.33-39
• /
• 1982

본 논문에서는 우리나라의 3개 단일목적댐(춘천, 청평, 화천)과 3개 다목점댐(소양, 안동, 대청)의 월 유하량 자료를 Thomas-Fiering 법과 조화함수법으로 50년간 모의발생하여 한계용량의 개념에 의하여 해석하였으며 조기별(월의 수) 단일목적 저수지와 다목적 저수지의 한계용량을 결정하였다. 그 결과 다음과 같은 Feller 형의 공식을 얻었다. (1) 단일목적 저수지 $R_n=2.8357 I\sqrt{n}$ (2) 다목적 저수지 $R_n=2.5145 I\sqrt{n}$ 그러므로 우리나라의 댐 지점에서의 월유하량은 Thomas-Fiering 법이 적합하며 Rippl의 누가곡선법에 의하지 않고 위의 공식에 의하여 주기별 한계용량을 쉽게 구할 수 있다.

• 한국수산과학회지
• /
• 제18권6호
• /
• pp.497-505
• /
• 1985

쓰시마 해류와 쿠로시오 해역의 9개 연안 정점의 30년간 ($1941{\sim}1970$) 순별 표면수온 자료에 대한 분석 (조화분석, 상관분석 및 스펙트럼 분석)을 통하여 동 해역 표면수온의 연변화와 연별변동을 구명하였다. 계절적 수온변화의 연평균과 연진폭은 해마다 차이가 있으며, 변동의 편차는 0.3 내지 $0.7^{\circ}C$정도이고, 연위상의 편차는 3 내지 4일 정도이다. 누년 평균적인 계절변화를 제거한 이상수온(temperature anomalies)은 약$1^{\circ}C$정도이며, 봄과 가을보다는 여름과 겨울에 이상수온의 변화가 심하다. 쓰시마 해역의 이상수온 쿠로시오 해역의 이상수온과 상관관계를 가지고 있다. 이상수온의 스펙트럼 분석에 의하면 주기 26개월의 준격년 진동(quasi-biennial oscillation)과 주기 14개월의 극조(pole tide) 주기에 따른 수온 변동이 나타난다

• International Journal of Aeronautical and Space Sciences
• /
• 제16권3호
• /
• pp.380-393
• /
• 2015

This study presents how we can evaluate stereo camera systems for the structural deformation monitoring. A stereo camera system, consisting of a set of stereo cameras and reflective markers attached on the structure, is introduced for the measurement and the stereo pattern recognition (SPR) method is utilized for the full-field structural deformation estimation. Performance of this measurement system depends on many parameters including types and specifications of the cameras, locations and orientations of them, and sizes and positions of markers; it is difficult to experimentally identify the effects of each parameter on the measurement performance. In this study, a simulation framework for evaluating performance of the stereo camera systems with various parameters has been developed. The maximum normalized root-mean-square (RMS) error is defined as a representative index of stereo camera system performance. A plate structure is chosen for an introductory example. Its several modal harmonic vibrations are generated and estimated in the simulation framework. Two cases of simulations are conducted to see the effects of camera locations and the resolutions of the cameras. An experimental validation is carried out for a few selected cases from the simulations. Using the simultaneous laser displacement sensor (LDS) measurements as the reference, the measurement errors are obtained and compared with the simulations.

• 대한후두음성언어의학회지
• /
• 제9권1호
• /
• pp.66-70
• /
• 1998

Background and Objectives : The managements of unilateral vocal cord palsy include type Ⅰ thyroplasty and arytenoid adduction. One type operation has been shown no satisfactory effect. We evaluated preoperative and postoperative speech of unilateral vocal cord palsy patients who received combined operation of type Ⅰ thyroplasty and arytenoid adduction to help for the management plan of unilateral vocal cord palsy patients. Materials and Methods : We reviewed the postoperative results and complication of 17 surgically treated patients of unilateral vocal cord palsy at Severance hospital from Nov. 1996 to Dec. 1997 retrospectively. They were received combined operation of type Ⅰ thyroplasty and arytenoid adduction. Their pre and post-operative speech were analyzed with MDVP(Multi-Dimension-Voice analysis Program) of CSL(Computerized Speech Lab). Results : After the operation, MPT(Maximal Phonation Time) was increased and MFR(Mean Flow Rate) was decreased in all patients. NHR(Noise to Harmonic Ratio) and VTI(Voice Turbulence Index) were decreased : liner, RAP(Relative Average Perturbation Quotient), PPQ(Pitch Period Perturbation Quotient), sPPQ(smoothed Pitch Period Perturbation Quotient), vFo(fundamental frequency Variation) were decreased : Shimmer, APQ(Amplitude Perturbation Quotient), sAPQ(Smoothed Amplitude Perturbation Qoutient), vAm(Peak Amplitude Variation) were decreased in all the patients. Conclusions : In unilateral vocal cord pals), combined operation of type Ⅰ thyroplasty and arytenoid adduction could obtain satisfactory postoperative voice. MDVP has many parameters and good method for evaluation of voice surgery.

• 대한후두음성언어의학회지
• /
• 제13권1호
• /
• pp.18-22
• /
• 2002

Background and Objectives : It has been pointed out that alcohol intake in human beings induces changes in voice register and maximum phonation time. These changes supposedly result from injection of the vibratory vocal folds. The purpose of this study was to clarify the voice changes associated with alcohol intake and the changes of laryngeal mucosa. Materials and Methods : The subjects included 29 volunteers, including 20 men and 9 women ranging in age from 22 to 31 years. Alcohol intake was accomplished by oral administration of 23% soju 1 bottle (255cc). Serum alcohol concentration levels were evaluated hourly for 3 h after ingestion of alcohol. Seven measurements were performed at pre-alcohol intake and post-alcohol intake hourly : fundamental frequency, jitter, shimmer, noise to harmonic ratio as the acoustic analysis, maximal phonation time, mean flow rate, and subglottal pressure as the aerodynamic analysis. The changes of laryngeal mucosa were evaluated by flexible laryngoscope at each measurement. Results : By comparing the acoustic and aerodynamic data and laryngeal mucosa before and after alcohol intake, there were not remarkable changes (p>0.05). Conclusion : The voice and laryngeal mucosa have not remarkably changed according to alcohol concentration in this study. Furthermore studies on the voice change induced by multiple alcohol concentrations are required.