• The Journal of the Acoustical Society of Korea
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• v.43 no.2
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• pp.200-206
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• 2024

Computing music similarity is an indispensable component in developing music search service. This paper proposes a relevance weight of each chromagram vector for cover song identification in computing a music similarity function in order to boost identification accuracy. We derive a music similarity function using the relevance weight based on the probabilistic relevance model, where higher relevance weights are assigned to less frequently-occurring discriminant chromagram vectors while lower weights to more frequently-occurring ones. Experimental results performed on two cover music datasets show that the proposed music similarity improves the cover song identification performance.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.3
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• pp.35-43
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• 2001

A method is newly presented to synthesize the modal impedances satisfying the desired coupling factor of a reflective (or hack ward) coupled-line. The synthesis is achieved by optimal perturbations of repeating null points of lobes inherent to the solution of the first order nonlinear differential equation for coupling. It is based on the synthesis method of nonlinear source distribution functions for the prescribed space factor pattern in the one-dimensional array antenna. Here, the conventional synthesis method for the even distribution function is extended to the odd case. Resulting modal impedances will have continuously varying profiles. The design procedure of asymmetrical and symmetrical couplers corresponding to the even and odd distribution functions, is examplified to show the generalization and the simplicity of the proposed method.

• Magazine of the Korea Concrete Institute
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• v.8 no.3
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• pp.197-207
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• 1996

Maturity is expressed as the integral of time and temperature of concrete above a datum temperature. The maturity concept proposes that concrete of the same mix at the same maturity has the same strength, whatever combination of temperature and time makes up that maturity. In this study, the Nurse-Saul function which was proposed to account for the effects of temperature and time on strength developrnent is used in computing maturity. After existing various functions are considered to relate concrete strength to the maturity value, new strength-maturity function is proposed. Tests ;ire conducted in order to determine d datum temperature and compare prechction value with measured concrete strength. The constants in proposed prediction equation are determined from test results, and the equation is adopted to predict the strength of slab. The slab was cast in the laboratory from the same batch of mold, and cores are cut from slab in order to estimate the actual strength. These values are used to compare with predicted value. The present study allows more realistic determination of early-age strength of concrete and can be efficiently used to control the quality in actual construction.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.2 s.54
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• pp.69-79
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• 2007

In this paper, a technique to detect structural damage and estimate its severity using peaks and zeros of frequency response functions (FRFs) is developed. The peaks in FRFs represent the natural frequencies of the structure and the zeros provide additional information. The characteristics of peaks and zeros are defined and the calculation procedure to obtain the peaks and zeros from the relationship between frequency response function and stiffness and mass matrices are clearly explained. A structural system identification theory which is utilizing the sensitivity of stiffness of a structural member to eigenvalues, i.e., peaks and zeros, is established. The proposed method can identify damage location and its severity, with natural and zero frequencies, by estimating structural stiffness of the structure in the process of making a analytical model The accuracy and feasibility is demonstrated by numerical models of a spring-mass system and a beam structure.

• Journal of Korean Society of Transportation
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• v.27 no.4
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• pp.127-135
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• 2009

Most traffic information that drivers receive while driving are stored in their short-term memory and disappear within a few seconds. Contemporary modeling approaches using a dummy variable can't fully explain this phenomenon. As such, this study proposes to use utility functions of real-time in-vehicle traffic safety information (IVTSI), analyzing its safety impacts based on empirical data from an on-site driving experiment at signalized intersection approach with a limited visibility. For this, a driving stability evaluation model is developed based on driver's driving speed choice, applying an ordered probit model. To estimate the specified utility functions, the model simultaneously accounts for various factors, such as traffic operation, geometry, road environment, and driver's characteristics. The results show three significant facts. First, a normal density function (exponential function) is appropriate to explain the utility of IVTSI proposed under study over time. Second, the IVTSI remains in driver's short-term memory for up to nearly 22 second after provision, decreasing over time. Three, IVTSI provision appears more important than the geometry factor but less than the traffic operation factor.

• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.653-658
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• 2014

This research was carried out to investigate equilibrium moisture content (EMC) of wood in outdoor locations in Korea. EMC was calculated using Hailwood-Horrobin equation for 73 different locations in Korea using the 1981 to 2010 climate normal data obtained from the Korea Meteorological Admnistration (KMA). Daegu showed the lowest values of EMC (11.5), and the highest EMC values (15.8) was found in Heuksando. Considering the season effect, summer (June, July, August) showed the highest values 15.3, followed by autumn (September, October, November) 13.7, winter (December, January, February) 12.2, and spring (February, March, April) 12.0. Monthly EMC showed the lowest values 11.6 in April and July showed the highest EMC values 16.1. The smallest changes in monthly EMC were found in Jeju island and Heuksando showed the largest values 8.7. A proper wood drying based on average EMC is more required in the regions with larger variation in EMC.

• Journal of Korean Society of Transportation
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• v.31 no.2
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• pp.33-44
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• 2013

The land use-transportation models typically have complicated model structure that is good for empirical execution but bad for theoretical probe. This complexity makes it very difficult to derive the first-order conditions for system optimization in tractable forms. Yu and Rhee (2011) and Rhee (2012) show how to simplify the derivative of the model's objective function with respect to policy variables in the computable general equilibrium model of land use and transportation. However, the travel demand in their model was fixed. This drawback fundamentally limits the applicability of their methodology in the planning field. We relax this restriction. Once this is done, we can employ the methodology developed in analyzing the impacts of various types of policy instruments in the models where land market is treated endogenously and transportation network is embedded.

• Proceedings of the Korea Water Resources Association Conference
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• 1998.05a
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• pp.62-67
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• 1998

낙동강 수계 다목적댐 하류 지역에 대한 홍수조절 의사결정 능력을 향상시키고자 강우- 유출 모형으로 선정된 저류함수법으로 낙동강 수계 다목적댐 하류부의 유역유출 체계를 먼저 구 성하였다. 저류함수법에 의한 낙동강 수계 유역유출 체계도는 유역의 물리적 특성을 감안하여 소 유역은 41개, 하동망은 28개로 구성하였다. 또한 수문학적 하도추적 기법이 갖는 결점을 보완하기 위하여 낙동강 본류 및 상류에 댐이 있는 금호강, 황강, 남강, 밀양강 등 1 지류 이상의 홍수추적 을 수리학적 모형으로 보완하여 유역유출 체계를 이원화하여 두시스템을 상호·연계할 수 있도록 하였다. 상기 두 시스템을 '93년 8월 홍수(8, 7~8, 15)에 시험 적용하였다. 모형수행 경과 홍수기 댐운영시 저류함수모형에 의한 강우 유출 모형과 수리학적 하도추적 모형을 통합한 시스템을 동시에 적용하여 상호 보완 과정을 통해 운영한다면 다목적댐의 홍수조절 의사결정능력을 향상시킬 수 있다고 판단된다. 본 연구에서는 사용자가 해석적 방법으로 유역에서 수문자료를 이용하여 매개변수를 대화식으로 산정할 수 있는 GUI 시스템을 EXCEL97 환경에서 개발하여 신뢰성 있는 Rating curve가 확보 상·하류에 위치한 12개 수위관측소에서 89개 홍수사상을 대상으로 유역의 매개변수를 산정하였다. 또한, 미계측 유역의 저류함수 관련 매개변수 확장을 위하여 12개 소유역 에 대한 매개변수의 평균값과 유역면적, 하도연장 및 경사, 유역의 사면경사 등의 지형인자들을 조합하여 지역화분석을 수행하여 미계측 유역의 매개변수 산정식으로 제안하였다. 본 회귀식으로 산정된 소유역별 매개변수를 '93년 8월 홍수(8, 7~8, 15)에 적용한 결과, 낙동강 수계 본류상 주요 수위관측소별 홍수량예측이 이근천공식 보다 양호한 결과를 주어 본 연구에서 제시한 유역의 매 개변수 회귀식은 미계측 유역의 매개변수 산정시 충분한 활용성을 입증하였다. 저류함수법에 의 한 낙동강 수계 다목적댐 하류부의 유역유출 체계도는 수리학적 하도추적 모형과의 연계와 유역 의 물리적 특성을 감안하여 현재의 홍수통제소에서 운영하는 홍수예경보 시스템의 유출체계도와 우리공사 물관리 상황실의 저수관리 모형의 유출체계도를 기준으로 재구성하여 다목적댐 하류부의 소유역은 41개, 하도망은 28개로 결정하였다.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.145-150
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• 2000

The adaptation for a right source on the retina consists of the light-dark adaptation's two curves for a time by the rod-cone receptor. We obtained the adaptation for a time to measure the threshold intensities, it was two decay curves by the center of a rod-cone break. It could be represented the dark adaptation by a exponential decay function consisting of $T_{min}$, $a_r$, $a_c$, $T_{0(r)}$, $T_{0(c)}$, $t_b$, $t_c$'s parameters. The curves of a $t_b$ below and a $t_b$ above showed the adaptation sensitivity of the cone and the rod. The exponential decay function was well applied to the dark adaptation in difference retinal positions, in contrally fixated fields, in luminous, as age etc. It could be used the decay parameter as the index because of representing the properties of the dark adaptation's function.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2029-2036
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• 2015

Hadoop MR(MapReduce) uses a partition function for passing the outputs of mappers to reducers. The partition function determines target reducers after calculating the hash-value from the key and performing mod-operation by reducer number. The legacy partition function doesn't divide the job effectively because it is so sensitive to key distribution. If the job isn't divided effectively then it can effect the total processing time of the job because some reducers need more time to process. This paper proposes the VPT(Virtual Partition Table) and has tested appling the VPT with a preponderance of data. The applied VPT improved three seconds on average and we figure it will improve more when data is increased.