• 한국항해항만학회지
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• 제43권5호
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• pp.273-280
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• 2019

This study developed an optimization model, defined as the IPS (Itinerary for Passenger Satisfaction), for a cruise ship to identify an itinerary that maximizes passenger satisfaction. A 0-1 integer programming model was developed to provide an optimal sequence of ports of call, assigning a destination to each day of the cruise. The concepts of the destination access network and the neighborhood of a destination were designed and manipulated to organize the complex network of destinations so that each next destination is selected within a practical overnight sail. The developed model can also be viewed as a reduced variant of the traveling salesperson problem with less constraints. A set of example tests shows that practical scenarios of the IPS with moderate cruise duration can be easily solved with light computation loads. Considering cruise ship passengers usually make their decisions not relying on only one destination but on an itinerary in its entirety, the purpose of this study was to identify itinerary alternatives to attract potential cruise passengers for attaining maximum occupancy level.

• 인터넷정보학회논문지
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• 제24권1호
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• pp.9-15
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• 2023

SPA(Single-Page Application)는 RESTful API와 통신을 위해 데이터의 변환을 필요로 한다. BFF(Backend for Frontend) 패턴은 이 변환을 서버에서 처리하고 있으나 통신 횟수를 증가시키고 개발과 배포를 어렵게 하는 문제가 있다. 본 연구에서는 SPA의 ViewModel과 RESTful API의 모델을 SPA에서 직접 매핑하는 아키텍처를 제안한다. 제안한 아키텍처는 RESTful API의 문서 모델인 OpenAPI 사양을 이용하여 RESTful API 모델과 ViewModel 간의 매핑 모델을 자동 생성한다. SPA의 통신 컴포넌트는 생성된 모델을 이용하여 RESTful API 데이터와 ViewModel을 자동 변환한다. 사례 연구를 통해 기존 BFF 방식과 비교한 결과 제안한 아키텍처는 BFF에 비해 높은 개발 생산성을 보였고 부하테스트 결과 BFF에 비해 약 6 %이상 낮은 서버 CPU 점유율을 기록하였다.

• 한국환경복원기술학회지
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• 제10권3호
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• pp.14-24
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• 2007

The purpose of this study was to investigate how the landscape characteristics and the physical factors of landscape would affect the preference for the Gapcheon in Daejeon Metropolitan City. The Gapcheon was divided in three sections of the outskirts, Expopark areas, and residential complexes. After selecting seven landscape points where the sections could be expressed best, photographs were taken both in the upstream and downstream direction. The questionnaire used to evaluate the river's landscape included 20 items of adverbs that described the form of the river and one item to rate the overall preference. By analyzing the 14 pictures taken, the occupancy rates of the landscape elements in terms of the sky, river, vegetation of the river, mountain, and artificial structures. Image factor analysis was conducted for each of the sections in order to analyze the landscape characteristics of the Gapcheon, and then regression analysis was conducted in order to analyze the relationships among the physical factors influencing the preference of the landscapes. The results were as follows : Factors that compose the visual characters of urban river were classified be the aesthetic factor, the emotional factor and the situation factor. These 3 factors showed a 65.8% total variance. The river landscape with the biggest preference was the one from the Daedeok Grand Bridge as the occupancy area of the mountain, sky, and river was large and distributed evenly and the vegetation of the river was in a good harmony with the surroundings. After carrying out regression analysis to examine the relationships between the visual preference of Gapcheon and the physical factors of landscape(the sky, river, vegetation of the river, mountain, and artificial structure), the following regressions model was made : PRE=5.906+0.017(river)-0.053(artificial structure)-0.060(vegetation of the river) (R-square=0.48).

• 보건행정학회지
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• 제17권2호
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• pp.68-90
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• 2007

Nurse staffing level is an important factor that influences the quality of health service and patient outcomes. This study was carried out to examine the current state of acute hospital nurse staffing and find out factors that affect the nurse staffing level. Nurse staffing of individual hospitals was measured using the number of registered nurses per 100 beds. Descriptive and multiple regression analyses were conducted using 592 acute care hospitals' data. Regression model included structure factors such as referral level, ownership, medical and general staffing, and financial outcome factors such as occupancy rate, inpatient and outpatient revenues. Market characteristics included strength of competition, supply of nurses, and income and health status level of consumers. The average number of nurses per 100 beds was 28 and showed a great variation according to the referral level. Regression model explained this variation as much as 76.87%. Hospital structure variables which affecting the hospital nurse staffing level positively were ICU bed ratio, the staffing level of specialist, training doctor and employees except doctor and nursing personnel, while the negative factor was nurse aid staffing level. General hospitals employed more nurses than hospitals. Among outcome characteristics, occupancy rate and the amount of health insurance inpatient revenue affected positively on the hospital nurse staffing level. The more supply of the new nurse and the higher consumer income and health status in the medical service markets, the more nurses were employed by the medical institutes. According to the study result, hospitals employed more nurses when they had more financial incentive by increasing nurses. This means appropriate hospital incentive policy and regulation policy, which hospital violate nurse staffing level have to pay penality, should be needed. Clarifying job description between nurses and nurse aids and the reentry program for unemployed experienced nurses will be helpful to increase nurse staffing level.

• 한국실내디자인학회논문집
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• 제25호
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• pp.280-289
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• 2000

The purpose of this study is to suggest a evaluation method and matching process model which derives suitable design firm for a client. Unlike the existing evaluation method, the suggested evaluation method and matching process for interior design firm allows a client specify his own needs. The evaluation methods utilizes designers experience record, past performance and customers post occupancy evaluation to derive design firms meeting clients requirements. With this method and matching process model, customers could access the design firms more efficiently and the design firms suitable for the clients needs could be suggested.

• 제어로봇시스템학회논문지
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• 제17권12호
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• pp.1219-1226
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• 2011

This paper proposes a novel approach to building an occupancy grid map using sonar data. It is very important for a mobile robot to recognize and construct its surrounding environments for navigation. However, the grid map constructed by ultrasonic sensors cannot represent a realistic shape of given environments due to incorrect sonar measurements caused by specular reflection. To overcome this problem, we propose an advanced sonar sensor model which consists of distance and shape factors used to determine the reliability of sensor data. Through this sensor model, a robot can build a high-quality grid map. The proposed method was verified by various experiments and showed that the robot could build an accurate map with sonar data in various indoor environments.

• 산업공학
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• 제14권1호
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• pp.67-78
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• 2001

This paper describes the simulation study which estimates the container crane efficiency in container terminal. In most simulation studies, it is assumed that container cranes are available at any time. Though the failures of container cranes don't occur often, they are very serious problems on terminal efficiency. As usual, the failures of container crane cause arrived ships to delay the departure time. In this study, a queueing simulation model for container terminal, which focuses on the failures of container cranes, is designed. The simulation approach appears to be the most appropriate one because it allows to avoid the usual exponential assumption on interarrivals of ships and service times of container cranes. Using the developed model, we tested the efficiency of container cranes considering failures with a real system size and performed the simulation experiment on real container terminal to validate the developed simulation model. The results of simulation experiment were analyzed using output statistics, which include the waiting times of vessels and yard tractors, the utilization for container cranes, and the berth occupancy rates.

• Industrial Engineering and Management Systems
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• 제12권3호
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• pp.207-223
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• 2013

Revenue management (RM) has been widely used to model products characterized as perishable. Classical RM model assumed that price is the sole factor in the model. Thus price adjustment becomes a crucial and costly factor in business. In this paper, an optimal pricing model is developed based on minimization of soft customer cost, one kind of price adjustment cost and is solved by Lagrange multiplier method. It is formed by expected discounted revenue/bid price integrating quantity-based RM and pricing-based RM. Quantity-based RM consists of two capacity models, namely, booking limit and overbooking. Booking limit, built by assuming uncertain customer arrival, decides the optimal capacity allocation for two market segments. Overbooking determines the level of accepted order exceeding capacity to anticipate probability of cancellation. Furthermore, pricing-based RM models occupancy/demand rate influenced by internal and competitor price changes. In this paper, a mathematical model based on game theoretic approach is developed for two conditions of deterministic and stochastic demand. Based on the equilibrium point, the best strategy for both hotels can be determined.

• 한국멀티미디어학회논문지
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• 제19권1호
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• pp.30-40
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• 2016

Recently, the competition among global IT companies for the market occupancy of the IoT(Internet of Things) is fierce. Internet of Things are all the things and people around the world connected to the Internet, and it is becoming more and more intelligent. In addition, for the purpose of providing users with a customized services to variety of context-awareness, IoT platform and related research have been active area. In this paper, we analyze third party instant messengers of Windows 8 Style UI and propose a digital forensic methodology. And, we are well aware of the Android-based map and navigation applications. What we want to show is GPS information analysis by using the R. In addition, we propose a structured data analysis applying the hierarchical clustering model using GPS data in the digital forensics modules. The proposed model is expected to help support the IOT services and efficient criminal investigation process.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제17권2호
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• pp.103-113
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• 2013

We analyze the queueing model for leaky bucket (LB) scheme with dynamic arrivals and token rates. In other words, in our LB scheme the arrivals and token rates are changed according to the buffer occupancy. In telecommunication networks, the LB scheme has been used as a policing function to prevent congestion. By considering bursty and correlated properties of input traffic, the arrivals are assumed to follow a Markov-modulated Poisson process (MMPP). We derive the distribution of system state, and obtain the loss probability and the mean waiting time. The analysis is done by using the embedded Markov chain and supplementary variable method. We also present some numerical examples to show the effect of our proposed model.