• 한국지역지리학회지
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• 제20권1호
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• pp.30-48
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• 2014

본 연구는 도시 간 상호작용 지수(지배력 지수, 상대적 강도 지수, 엔트로피 지수)를 활용하여 출근 흐름과 업무 흐름, 화물 흐름에 있어서 수도권 도시 네트워크의 구조적 특성을 분석하였다. 분석 결과는 수도권의 도시 네트워크가 흔히 네트워크형 도시체계론에서 말하는 수평적이고 상호보완적이며 양방향과 규모 중립적이기 보다는 매우 규모 의존적이고, 수직적이고 최고차 중심도시에 의존적하는 지배 종속적 구조를 가지고 있는 것으로 나타났다. 출근 업무 흐름에 비해 화물 흐름의 네트워크가 다소 균형적이기는 하지만, 상호작용의 계층 구조, 흐름의 상대적 강도, 균형성 등 모든 면에서 출근 업무 흐름이든, 화물 흐름이든 서울과의 상호작용이 결정적이다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.428-430
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• 2018

유치원이나 어린이집 통학 차량의 탑승 사고는 여러 가지 정책적 조치에도 불구하고 꾸준히 발생하고 있다. 이를 최소화하기 위해서는 운전자가 간편하게 조작할 수 있는 차량 탑재형 안전 통학 관리 소프트웨어와 아동의 안전 통학 여부를 관리하고 부모에게 적시에 알려주는 모바일 앱의 병행 사용이 필요하다. 본 논문은 이 중 안전 통학 관리 모바일 앱의 설계와 구현에 대하여 설명한다.

• Journal of applied mathematics & informatics
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• 제5권3호
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• pp.819-826
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• 1998

The purpose of this paper is to prove the following results; (1) Let R be a prime ring of char $(R)\neq 2$ and I a nonzero left ideal of R. The existence of a nonzero symmetric bi-derivation D : $R\timesR\;\longrightarrow\;$ such that d is sew-commuting on I where d is the trace of D forces R to be commutative (2) Let m and n be integers with $m\;\neq\;0.\;or\;n\neq\;0$. Let R be a noncommutative prime ring of char$ (R))\neq \; 2-1\; p_1 \;n_1$ where p is a prime number which is a divisor of m, and I a nonzero two-sided ideal of R. Let $D_1$ ; $R\;\times\;R\;\longrightarrow\;and\;$ $D_2\;:\;R\;\times\;R\;longrightarrow\;R$ be symmetric bi-derivations. Suppose further that there exists a symmetric bi-additive mapping B ; $R\;\times\;R\;\longrightarrow\;and\;$ such that $md_1(\chi)\chi ＋ n\chi d_2(\chi)=f(\chi$) holds for all $\chi$$\in$I, where $d_1 \;and\; d_2$ are the traces of $D_1 \;and\; D_2$ respectively and f is the trace of B. Then we have $D_1=0 \;and\; D_2=0$.

• 대한수학회지
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• 제45권2호
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• pp.425-433
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• 2008

Let R be a ring with identity $1_R$ and let U(R) denote the group of all units of R. A ring R is called locally finite if every finite subset in it generates a finite semi group multiplicatively. In this paper, some results are obtained as follows: (1) for any semilocal (hence semiperfect) ring R, U(R) is a finite (resp. locally finite) group if and only if R is a finite (resp. locally finite) ring; U(R) is a locally finite group if and only if U$(M_n(R))$ is a locally finite group where $M_n(R)$ is the full matrix ring of $n{\times}n$ matrices over R for any positive integer n; in addition, if $2=1_R+1_R$ is a unit in R, then U(R) is an abelian group if and only if R is a commutative ring; (2) for any semiperfect ring R, if E(R), the set of all idempotents in R, is commuting, then $R/J\cong\oplus_{i=1}^mD_i$ where each $D_i$ is a division ring for some positive integer m and |E(R)|=$2^m$; in addition, if 2=$1_R+1_R$ is a unit in R, then every idempotent is central.

• Kyungpook Mathematical Journal
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• 제55권1호
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• pp.1-12
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• 2015

Let R be a ring and $D:R^n{\longrightarrow}R$ be n-additive mapping. A map $d:R{\longrightarrow}R$ is said to be the trace of D if $d(x)=D(x,x,{\ldots}x)$ for all $x{\in}R$. Suppose that ${\alpha},{\beta}$ are endomorphisms of R. For any $a,b{\in}R$, let < a, b > $_{({\alpha},{\beta})}=a{\alpha}(b)+{\beta}(b)a$. In the present paper under certain suitable torsion restrictions it is shown that D = 0 if R satisfies either < d(x), $x^m$ > $_{({\alpha},{\beta})}=0$, for all $x{\in}R$ or ${\ll}$ d(x), x > $_{({\alpha},{\beta})}$, $x^m$ > $_{({\alpha},{\beta})}=0$, for all $x{\in}R$. Further, if < d(x), x > ${\in}Z(R)$, the center of R, for all $x{\in}R$ or < d(x)x - xd(x), x >= 0, for all $x{\in}R$, then it is proved that d is commuting on R. Some more related results are also obtained for additive mapping on R.

• 농촌계획
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• 제23권3호
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• pp.121-131
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• 2017

Although the educational facility are an important considerations on a social equity standpoint, educational environment in rural areas has been continuously deteriorated by numerous social problems such as decreasing birth rate and increasing of local school closing. The purpose of this study is to evaluate the accessibility of educational environment in rural areas on village level. First, we evaluate physical accessibility based on legally defined commuting distance. Second, the implication of village population of potential accessibility is analyzed. Lastly, the facility centrality index of each village is estimated for assessing the relations of educational accessibility. The main results of this study are as follows; (1) The accessibility of most villages in Pyeongchang-gun is vulnerable that 81.10% for elementary school, 73.17% for middle school, and 82.32% for high school, respectively; (2) The average commuting distance per student considering estimated number of students for each educational facilities indicated 2.75km for elementary school, 4.37km for middle school, and 5.79km for high school; (3) the facility centrality index is highly correlated to educational facilities but not to village population.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1886-1894
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• 2009

The widening national capital area of Korea has caused a traffic jam problem with increasing commuting hours. In addition, as the economic crisis goes on, the people moving to the outside of a city has increased. So we expect that the expansion of this metropolitan area will do grow and it will cause a more severe traffic jam in the near future. Therefore, We will study about 'Rapid Railroad Operation in Metropolitan Area' to solve this problem and improve rail's competitive power as a reasonable transportation method. The Rapid Railroad can sharply reduce commuting hours. Also, it is more eco-friendly transportation than the others. Through many cases revealed in both domestics and overseas, we will solve the problem of a traffic jam getting senous m metropolitan area. After studying successful cases of overseas, rapid railroad, such as France and Japan, we will study domestic cases of Yongsan$\sim$Dong-inchoen, Guro$\sim$Cheonan and Gaehwa$\sim$Sin-nonhyeon, and comparison will do made among these case. In conclusion, The introduction of Rapid Railroad show the effective plan for strengthen the competitiveness and solve the traffic problem.

• 대한치과기공학회지
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• 제11권1호
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• pp.47-63
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• 1989

The study was made to clarify the degree of fatigue of dental technicians in service at the general &local hospital or the dental laboratories in the large cith of korea. The objectives of this study were 235 dental technicians who replied the questionaire which was sent by postal service out of 600 dental technicians selected by random sampling among the workers of the each dental laboratory. The instruments used in this study was the same one as developed by Industry Fatigue committee of Japan Industry Hygiene Association. This instrument was included total 30 items which is consisted of 10 perceived symptoms of fatigue in physical, mental and neuro-sensory dimension respectably. Reliability was tasted with the data of objectives, in which value of Cronbach's $\alpha$ was 9457. The following results were obtained. 1. It was revealed that the influencing demographic variables on the perceived symptoms of fatigue of dental technicians were sex, age, marital status, educational background, job carrier, working part, working hour and commuting hour. The shorted the age or job carrier, thge higher dearee of the perceived symptoms of fatigue. The longer working hours of commuting hours, the higher degree of the perceived symptoms of fatigue. The degree of the perceived symptoms of fatigue in females, unmarried person, the one with higher educational background, workers except orthodontic appliances and poorcelain contouring were higher than the other group. 2. The higher degree of the rest & leisure condition, the lower degree of the physical, mental and neuro-sensory perceived symptoms. 3. The higher degree of environmental condition of the working, the lower degree of the physical, mental and neurosensory perceived symptoms.

• 농촌계획
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• 제18권3호
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• pp.165-174
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• 2012

Development of transportation and communication technology has affected our daily life and has caused to separate residential places from working places. Particularly in rural areas, the life zones are incorporated into larger towns or urban areas due to their lack of cultural, social and economic infrastructures. Thus, the analysis of the depended region and the life zone is important for the planning of regional revitalization programs and related project. The purpose of this study is to propose a regional dependency model (RDM) using the origin-destination(O-D) matrix of commuters and compare it with the Nystuen & Dacey model for regional correlation. The regional characteristics are analysed and our RDM were tested using the commuting data on Seoul metropolitan area(Seoul, Gyeong-gi, Incheon) and Chungchung area. The regional correlation model can only explain the determination of regional interaction without considering the direction of regional correlation but our model can show the direction of regional dependencies.

• The Journal of Asian Finance, Economics and Business
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• 제10권2호
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• pp.183-193
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• 2023

This paper proposes and examines the economic impact of infrastructure improvement on the San-En-Nanshin region in the Chubu area of Japan. We develop a single transportation computable general equilibrium (CGE) model for each subregion within the San-En-Nanshin region. The explicit modeling of the transportation infrastructure is defined based on interregional commuting flows and business trips, considering the spatial structure of the San-En-Nanshin economy. A CGE model is integrated with an interregional transportation network model to enhance the framework's potential for understanding the infrastructure's role in regional development. To evaluate the economic impact of transportation improvement, we analyze the interrelationship between travel time savings and regional output and income. The economic impact analysis under the CGE framework reveals how transportation facilities and systems affect firm and household behavior and therefore induce changes in the production and consumption of commodities and transportation services. The proposed theoretical model was tested by using data from the 2005 IO tables of each subregion and the 2006 transport flow dataset issued by the Ministry of Land, Infrastructure, Transport, and Tourism in Japan. As a result, the paper confirms the positive effect of transportation investment on the total output and income of the studied region. Specifically, we found that while economic benefits typically appear in urban areas, rural areas can still potentially benefit from transportation improvement projects.