• Journal of KIISE:Software and Applications
• /
• v.26 no.1
• /
• pp.25-39
• /
• 1999

지리 정보 시스템에서 공간 분석을 위해 사용되는 중요한 연산인 공간 조인은 대상이 되는 공간 객체의 수가 증가함에 따라서 연산 시간이 지수적으로 증가하는 특징을 가지고 있다. 그러므로 다량의 공간 데이터에 대해서 공간 연산시간을 줄이기 위한 병렬처리가 필요하다. 이 논문에서는 비겹침 정규분할 방식의 사분트리를 이용한 공간 조인 알고리즘을 제시하고 MIMD 구조 및 공유 디스크 방식의 병렬 처리시스템에 적용하여 성능을 평가한다. 사분트리를 이용한 공간조인 방법으로서 중복 표현된 공간객체를 줄이기 위한 사분면(quadrant)의 병합 방법,영역 제한을 통해 연산 대상 객체를 줄이기 위한 사분면의 분할 방법, 그리고 병합 및 분할 방법을 혼용하여 공간 조인 연산의 숫자를 최소화하는 혼합 방법을 제시한다. 실험 평가에서는 각 방법들을 병렬 처리 시스템에 적용하여 여과단계 및 정제단계에서의 연산량과 수행 시간을 통해 성능을 비교 평가한다. 실험결과, 여과 단계에서는 분할 방법이 가장 우수했지만, 정제 단계에서는 병합 방법이 가장 우수했다. 따라서 전체적인 고려할 때 두 방법의 장점을 수용한 혼합 방법이 가장 우수한 성능을 나타냈다.

• The Korean Journal of Applied Statistics
• /
• v.7 no.1
• /
• pp.131-140
• /
• 1994

In order to find the identification function from data and to apply the identification function for the pattern classification, we consider the existing problem of the number of patterns in such data. In this paper, a new criteria for the identification of Gaussaian mixture distribution could be established as a charateristic of the sample variance, which is a bootstrap estimate of the sample variance. We examine the properties and fittness of the criteria through a large scale of computer simulations.

• Journal of Internet Computing and Services
• /
• v.10 no.2
• /
• pp.143-151
• /
• 2009

In this paper, we define Achieved Goodput(AG), Achieved Goodput Index(AGI) and Normalized Achieved Goodput Index(NAGI) in order to evaluate TCP schemes over heterogeneous wireless networks. These metrics contain a concept of achievement, the ability of accomplishing an objective in a given network situation unlike performance metrics commonly used to evaluate TCP schemes.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2013.11a
• /
• pp.449-452
• /
• 2013

최근 산업, 무역 및 유통 기업들은 수 많은 물류 자원에 IT 기술이 도입되어 운용되고 있다. 이러한 기업들은 물류 비용을 절감하기 위해 자동차 생산 분류와 물류 수송 부분으로 이어진다. 물류 분야 중 자동차 생산 분류에 선재 관리를 통해 기업과 기업으로 서로 운송되어 분류되어 있으며, 차량 선재 분배를 위해 POS에서 나온 데이터를 바코드를 사용하게 된다. 그러나, 이러한 선재의 문제점은 작업자의 분류지를 일일이 보면서 확인을 통해 작업을 하고 있으며, 작업자의 누락 혼합 발생된 물류 납품시 타사 기업으로 선재의 혼합, 누락 등으로 2차적 피해가 발생하게 된다. 따라서, 본 연구에서는 차량 선재의 분류에 대한 2D 스캐너 기반의 프로세서와 시스템을 포함하고 선재 물류 분류 장치를 통해 특성을 설계하고 현장을 개선하고자 한다.

• Journal of the Korean Geotechnical Society
• /
• v.20 no.9
• /
• pp.125-131
• /
• 2004

A series of unconfined compression tests were carried out firstly to investigate mechanical behaviors of Lightweight Foamed Soil (LWFS) which is composed of dredged soils, cement and air foam. And secondly, to compare the difference of mechanical characteristic of LWFS with previous research conclusions (Yoon & Kim,2004) by using different dredged soils sampled at Joong-Ma in Gwangyang harbor area. Based on numberous laboratory experiments, it was found that deformation coefficient $(E_{50})$ of LWFS increases with increasing cement contents but decreases with increasing initial water contents of dredged soils. Appropriate regression formula (normalizing factor scheme) which considers relationship between LWFS composing elements, initial water contents of dredged soils, cement, air foam, and uniaxial compression strength or LWFS is proposed for practical applications. Finally, it was clear that, to apply LWFS method to practical projects, certain laboratory test would be necessary to take considerations of soil locality because mechanical charac-teristics of LWFS were surely dependent upon their sampled locations and properties.

• Journal of the Korean Chemical Society
• /
• v.59 no.4
• /
• pp.271-279
• /
• 2015

The critical micelle concentration (CMC), the counter ion binding constant (B) and the aggregation number (N^* ) for the mixed micellization of sodium dodecanoate and sodium n-octanoate as two anionic surfactants have been investigated by means of electric conductivity and light scattering. As its experimental results are found to be deviated from ideal mixed model, thus two different kinds of regular solution models such as Rubingh and Motomura are used for interpreting our experimental data. The stability of the mixed micelles has been confirmed from the negative values of the standard Gibbs energy of mixed micellization ΔG^micel,0 over all compositions and the measured values of ΔG^micel,0 agreed with the theoretical ones within the experimental error.

• The Korean Journal of Applied Statistics
• /
• v.24 no.3
• /
• pp.547-557
• /
• 2011

In this paper we developed a statistical model for traffic volume data which collected from a spot of specific local state road. One peculiar property of daily traffic data is that it has bimodal shape which have two peaks on times of both going to office and coming back to home. So, various mixture models of circular distribution are suggested for bimodal traffic data and EM algorithms are applied to estimate the parameters of the suggested models. To compare the accuracy of the suggested models, classical regressions with dummy variables are also considered. The suggested models for traffic volumn data can be effectively used to estimate missing values due to measuring instrument disorder.

• Journal of the Korean Chemical Society
• /
• v.50 no.2
• /
• pp.137-140
• /
• 2006

In this report, Europium doped strontium barium gallium silicate ((Sr,Ba)2Ga2SiO7:Eu2+) phosphor has been synthesized by conventional solid-state method and investigated luminescent characteristic. Appropriate proportions of the raw materials were mixed in an agate mortar with acetone to obtain starting mixtures. Also, this phosphor was prepared by simple process under the reduction atmosphere (25% H2/75% N2). This phosphor can be applicated to the green phosphor for white LED because it has green emission band (513 nm), which emits efficiently under the 405nm excitation energy.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.28 no.3
• /
• pp.171-176
• /
• 2016

The distribution shapes of air and water temperatures are basic and essential information, which determine the frequency patterns of their occurrence. It is also very useful to understand the changes in long-term air and water temperatures with respect to climate change. The typical distribution shapes of air and water temperatures cannot be well fitted using widely used/accepted normal distributions because their shapes show multimodal distributions. In this study, Gaussian mixture distributions and kernel distributions are suggested as the more suitable models to fit their distribution shapes. Based on the results, the tail shape exhibits different patterns. The tail is long in higher temperature regions of water temperature distribution and in lower temperature regions of air temperature distribution. These types of shape comparisons can be useful to identify the patterns of long-term air and water temperature changes and the relationship between air and water temperatures. It is nearly impossible to identify change patterns using only mean-temperatures and normal distributions.

• Journal of Advanced Marine Engineering and Technology
• /
• v.41 no.1
• /
• pp.111-117
• /
• 2017

The arrival time of rescue ships is very important in the event of distress. This paper presents the development of experimental data to calculate the arrival time of rescue ships. The ship's traffic probability distribution was used. Mokpo Port was selected as the area of study, and AIS data for a 1 year period were used. For the ship's traffic probability distribution, a gateline was established. The lateral range distribution was calculated and fitted to the normal distribution and two Gaussian mixture distributions (GMD2), and each parameter was extracted. After the locations of ${\mu}$, ${\mu}{\pm}1{\sigma}$ of the normal distribution and ${\mu}_1$ of the two Gaussian mixture distribution(GMD2) were set as waypoints, the location and probability were determined. A scenario was established in relation to each type of parameter. Thus, the arrival time can be calculated.