• 한국항행학회논문지
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• 제17권5호
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• pp.506-515
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• 2013

무선 인지 네트워크의 많은 연구는 한 번의 스펙트럼 센싱 수행으로 한 개의 데이터 슬롯을 전송하는 프레임 구조에 대하여 연구하였다. 프레임 길이가 짧은 경우, 데이터 전송률이 낮아지는 문제가 있다. 본 논문에서는 한 번의 스펙트럼 센싱 수행으로 다수의 데이터 슬롯을 전송하는 군집형 데이터 슬롯 구조에 대해서 연구한다. 이를 위해서 Chapman-Kolmogorov 방정식을 이용하여 선순위 사용자의 전송 확률을 모델링하고 이를 이용하여 후순위 사용자의 전송률을 최대화하기 위한 최적화 문제를 제시한다. 최적화 문제의 해를 구하여 최적의 스펙트럼 센싱 시간과 데이터 슬롯의 길이와 군집할 데이터 슬롯의 수를 도출한다.

• 무역학회지
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• 제44권3호
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• pp.253-269
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• 2019

This study examines the utilization effect of FTA on the sales and profit of the secondary auto-part suppliers in two aspects: 1) firm-level survey on the utilization of FTA and 2) statistical inference on the FTA effects on their sales and profit. We use the GLS statistical technique, panel and survey data of 130 secondary auto-part suppliers in the Daegu and Kyungpook area in 2007-2016. The evidence shows that the secondary auto-part suppliers struggle to prepare documents for the FTA certificates of origin due to their small firm size, although they utilize the FTA at the relatively high rate of 92 percent. Statistical evidence shows that an increase in the export of the first vender significantly affects the sale of the secondary auto-part vendors, but not their profit. The low profit and high managing cost of utilizing the FTA deteriorate the utilization effect of the FTA of the secondary auto-part vendors, which is a key factor in a global supply chain and for the competitiveness of the automobile industry. Government policies are required for the secondary auto-part suppliers to utilize the FTA more effectively and share the benefits of tariff reduction with first auto-part vendors under FTA transaction.

• Journal of the Korean Data and Information Science Society
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• 제28권6호
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• pp.1539-1545
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• 2017

본 연구는 확률과 통계의 내용을 올바르게 지도할 수 있는 역량을 갖춘 수학 교사를 선발하기 위한 중등학교 수학교과 임용고사문제 중에서 확률과 통계 영역의 출세 경향을 분석하고, 앞으로의 출제 방향과 수준에 대하여 논의하고자 한다. 동시에 학교 수학 교사들에게 확률과 통계 단원을 지도하기 위해서 갖추어야 할 내용에 대한 일반적인 가이드를 제시하고자 한다. 첫째, 2015년 개정 고시된 교육과정의 수학 교과 중에서 확률과 통계 단원의 편제와 내용체계, 주요 변화 내용을 조사한다. 둘째, 중등교원임용시험에 15년간 출제 된 확률과 통계 단원의 문제들을 분석한다. 셋째, 기존의 출세 문제들이 중등학교의 확률과 통계를 올바르게 교육할 수 있는 자질을 갖춘 교사를 선발할 수 있는지에 대하여 검토한다. 마지막으로, 앞으로의 출제 내용, 범위, 수준, 그리고 방향에 대해서 논의한다. 결론적으로 4차 산업혁명시대를 맞이하여 빅 데이터의 중요성을 감안한다면 자료와 확률에 대한 통계적사고, 탐색적자료분석, 표본조사, 통계적 추론 그리고 공학적 도구의 활용 등의 출제가 더욱 필요하다고 본다.

• 한국통신학회논문지
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• 제18권9호
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• pp.1404-1411
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• 1993

음성 통신과는 달리 데이타 신호전송은 불규칙하게 순간적으로 발생하는 선로장애에 크게 영향을 받는다. 이런 장애로 인해 때로는 송수신기 사이의 동기를 잃게되어, 강제적으로 재 동기시키지 않는한. 회복이 스스로 되지 못한다. 따라서 이러한 순간적인 장애에 의한 동기 손실에 적절히 대처하기 위해 데이타통신 장비에 효율적인 검출기가 필요된다. 본 논문에서는 부속데이타 채녈이 주데이타 채널에 같이 통합되어있는 데이타 송수신기에 적당한 검출기를 설계하였다. 검출용 신호를 원래의 부속채널 데이타와 함께섞어 기존 채널의 운영에 영향이 없게 부속채널을 통해 보낸다. 데이타 전송중에 계속해서 동작하도록, 변형된 up/down 카운터를 이용한 검출방식을 사용한다. 설계된 검출기의 성능이 수학적으로 분석되었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.47-50
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• 2006

Tsunami disaster caused great damages and very large victims especially when occurs in urban area along coastal region. Therefore information of evacuation in a map is very important for disaster preparedness in order to minimize the number of victims in affected area. Here, information generated from remote sensing satellite data (SPOT 5 and DEM) and secondary data (administration boundary and field survey data) are used to simulate evacuation route and to produce a map for Padang City. Vulnerability and evacuation areas are determined based on DEM. Landuse/landcover, accessibility areas, infrastructure and landmark are extracted from SPOT 5 data. All the data obtained from remote sensing and secondary data are integrated using geospatial modelling to determine evacuation routes. Finally the simulation of evacuation route in Padang City for tsunami preparedness is provided based on the parameters derived from remote sensing data such as distances from shelters, save zones, city's landmarks and the local community experiences how they can survive with the disaster.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2006년도 PROCEEDINGS OF JOINT CONFERENCEOF KDISS AND KDAS
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• pp.229-233
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• 2006

In teaching statistics in the secondary school, most math teachers do it and students enjoy it well before 11th grade. But, both of teachers and students feel statistics hard at 11th grade, which has been contained permutations, combinations, random variables, probability distributions, hypotheses and tests for normal distribution. In this study, we explore the efficient teaching methods of statistics for math teachers and also find many students enjoying it.

• Communications for Statistical Applications and Methods
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• 제6권3호
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• pp.755-760
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• 1999

In multivariate stratified sampling surveys it is general to use a few stratification variables which are highly correlated with the important variables at design stage. But there might be some secondary study variables which are not so highly correlated with those stratification variables. In that case it is not efficient to use the same type of estimator due to the secondary variables as the one base on the important variables. A post-stratified estimation is proposed to increase the efficiency of the estimator with existence of secondary variables. The proposed method is illustrated with a set of fishery household population survey data.

• 한국산림과학회지
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• 제97권5호
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• pp.501-507
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• 2008

The data of crown width with 4 directions, DBH, tree height, and coordinate for sample trees were collected from 30 permanent sample plots in secondary fore st of the Maoershan Experimental Forestry Farm, Northeast China. In this paper, the competition of individual trees in stand were discussed for secondary forest by using iterative Hegyi competition index and crown overlap index that represented the competitive and cooperative interactions among neighboring trees. Active competitors of subject tree in the competition zone were selected to calculate the iterative competition index. Using the results of crown classification based on the equal crown projection area, a new distance dependent competition index called crown overlap index (COI) was developed for secondary forest. The COI performed well in describing the crown competition rather than crown competition factor (CCF). The individual-based competition index discussed in this paper will provide more precise for developing individual tree growth models for secondary forest and it can also use to adjust the stand structure for spatial optimal management.

• 대한기계학회논문집B
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• 제27권8호
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• pp.1150-1157
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• 2003

Nonlinear relationship between Reynolds stresses and the rate of strain of nonlinear k-$\varepsilon$models is evaluated theoretically by using the boundary layer assumptions against the turbulence-driven secondary flows in noncircular ducts and then their prediction performance is validated numerically through the application to the fully developed turbulent flow in a square duct. Typical predicted quantities such as mean axial and secondary velocities, turbulent kinetic energy and Reynolds stresses are compared with available experimental data. The nonlinear k-$\varepsilon$ model adopted in a commercial code is found to be unable to predict accurately duct flows with the prediction level of secondary flows one order less than that of the experiment.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.204-211
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• 2002

Combustion experiments are carried out to obtain the fundamental data for application of a internally circulating fluidized bed combustor to the combustion of paper sludge wastes. Experimental parameters are identified as secondary air ratio, sludge weight and water contents. The secondary air ratio was varied from 0 to 20% and water content was 14%, 25%, 35%, 45%, 62% and sludge weight was 30g, 60g, 90g. As a result, carbon conversion ratio was higher than injection of primary air. Emission of CO and NOx reduced with an increase of secondary air injection.