• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.143-153
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• 2006

This paper annually estimates the economies of density, scale and scope with the data of cost and output of 27 leading air carriers to suggest the political findings and strategies of raising the cost efficiency of our air transport industry. The estimation results and their implications are as follows. First, KAL and Aha would reduce their cost if they could increase international route density. Second, KAL and AAR would reduce their cost if they could expand the network but save their cost more effectively if they could increase international route density rather than expand the network. Third, the minimum efficient scale that minimize average cost of two national flag carriers which operate by the present output ratio among domestic passenger, international passenger and freight appears to be larger than each present output level of KAL and AAR. Meanwhile, it appears that minimum efficient scale of small size low cost carriers which operate domestic-oriented route is much smaller than minimum efficient scale of national flag carriers. Finally, it appears that there exists the diseconomies of scope between domestic passenger and the other outputs, that is, international passenger and freight and therefore save their cost if freight output ratio is higher and domestic passenger output ratio is lower than the Present level.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.9
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• pp.723-732
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• 2001

In this paper, the neurofuzzy controller of optically guided AGV is proposed to improve the path-tracking performance A differential steered AGV has front-side and rear-side optical sensors, which can identify the guiding path. Due to the discontinuity of measured data in optical sensors, optically guided AGVs break away easily from the guiding path and path-tracking performance is being degraded. Whenever the On/Off signals in the optical sensors are generated discontinuously, the motion errors can be measured and updated. After sensing, the variation of motion errors can be estimated continuously by the dead reckoning method according to left/right wheel angular velocity. We define the estimated contour error as the sum of the measured contour in the sensing error and the estimated variation of contour error after sensing. The neurofuzzy system consists of incorporating fuzzy controller and neural network. The center and width of fuzzy membership functions are adaptively adjusted by back-propagation learning to minimize th estimated contour error. The proposed control system can be compared with the traditional fuzzy control and decision system in their network structure and learning ability. The proposed control strategy is experience through simulated model to check the performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2878-2884
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• 2015

Twitter, one of online social network services, is one of the most popular micro-blogs, which generates a large number of automated programs, known as tweet bots because of the open structure of Twitter. While these tweet bots are categorized to legitimate bots and malicious bots, it is important to detect tweet bots since malicious bots spread spam and malicious contents to human users. In the conventional work, temporal information was utilized for the classficiation of human and bot. In this paper, by utilizing geo-tagged tweets that provide high-precision location information of users, we first identify both Twitter users' exact location. Then, we propose a new tweet bot detection algorithm by using both an entropy based on geographic variable of each user and device information of each user. As a main result, the proposed algorithm shows superior bot detection and false alarm probabilities over the conventional result which only uses temporal information.

• Journal of the Korean Society for information Management
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• v.35 no.3
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• pp.11-39
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• 2018

The study examines the research trends of doctoral dissertations in Library Science and Information Science published in the U.S. for the last 5 years. Data collected from PQDT Global includes 1,016 doctoral dissertations containing "Library Science" or "Information Science" as subject headings, and keywords extracted from those dissertations were used for a network analysis, which helps identifying the intellectual structure of the dissertations. Also, the analysis using 103 subject heading keywords resulted in various centrality measures, including triangle betweenness centrality and nearest neighbor centrality, as well as 26 clusters of associated subject headings. The most frequently studied subjects include computer-related subjects, education-related subjects, and communication-related subjects, and a cluster with information science as the most central subject contains most of the computer-related keywords, while a cluster with library science as the most central subject contains many of the education-related keywords. Other related subjects include various user groups for user studies, and subjects related to information systems such as management, economics, geography, and biomedical engineering.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.562-570
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• 2018

New physical properties of polymer materials were obtained by blending two or three different type of polymers. TPE is used widely in the display, automotive and electronics industries. Consumers have sought emotionally more sensitive and advanced interior automotive parts. A polymer with high foamibility (Ed note: Please check this.) and flowability would be more plausible. TPE composed of foam is a good polymer material to satisfy these trends. In this research, two different TPE were tested, focusing on foamibility and flowability. Two type of TPE were prepared. The first was blended Homo-PP, oil and SEBS. The second was Co-PP, oil and SEBS. The blending temperatures were $180^{\circ}C$, $190^{\circ}C$, and $260^{\circ}C$(second one). The blending speed was 50rpm and blending time was 5 min. The MI of the blended material was affected by the MI of PP and not affected by the blending temperature. The hardness and tensile elasticity were less affected by the MI of PP and blending temperature. The hardness and tensile elasticity were lower at a higher SEBS/Oil content ratio. The soft touch feel was higher with high SEBS/Oil contents. The IPN (Interpenentration polymer network) structure was observed by dissolving the SEBS/Oil layer in xylene. Strain-hardening phenomena also was observed. TPE behaves in a rubber and foamed closed-cell improved its stability.

• Journal of Distribution Science
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• v.15 no.2
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• pp.79-90
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• 2017

Purpose - Cargo Distribution O2O Business Model is the form of business that connects the cargo and empty cargo-truck based on mobile online platform. In Korean cargo distribution market, FIN(Freight Information Network) is the only model that represents O2O Business Model. The purpose of this paper is investigating the recognition of driver who is the only source of income toward cargo distribution O2O Business Model, and based on the investigated recognition of trucker, suggesting strategic implication. Research design, data, and methodology - PESTLE methodology which is massive environment analysis, and 5 Forces Model when analyze the present and future of cargo distribution O2O business market of industrial structure analysis were used as investigation methodology. Also structured questionnaire was used for trucker's recognition investigation. Based on collected 196 structured effective questionnaires organized with 26 questions were analyzed using statistics package. Results - 51.3% of responded driver is non-differentiated, deprofessionalize form that transport all types of cargo. 95.4% recognize cargo distribution O2O Business Model, FIN is needed, especially during back-hall(94.7%). As a payment method, monthly due is preferred(73%), but it is also needed to pay annual due and pay whenever cargo and cargo-truck are connected(24.5%). Trucker prefer FIN operation corporation which has rich supply(85.2%), and is liberal in supply in any domestic area(75.5%). Conclusions - First, 91% was the member of FIN, and 95% of non-member recognized FIN is needed. 83% of them has the intent to be the member of FIN. Second, besides of monthly due as payment method of FIN, 25% has positive recognition toward new payment method. The new payment method means paying annual due and pay whenever cargo and cargo-truck are connected. Third, because of information imbalance about the cargo and cargo-truck among, operators whose business goal is FIN, it was investigated that transportation fee is low and commission charge of broker is high. The core of Korean Cargo Distribution O2O Business Model, FIN, is online platform that matches cargo and cargo-truck. Therefore, FIN operator should minimize the amount of single transportation of trucker. This study suggests the development of shipper using FIN, diversify distribution channel, suggesting backhaul toward trucker as solution to FIN operator.

• Journal of KIISE:Software and Applications
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• v.37 no.1
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• pp.60-73
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• 2010

This paper aims to describe KorLexClas 1.5 which provides us with a very large list of Korean numeral classifiers, and with the co-occurring noun categories that select each numeral classifier. Differently from KorLex of other POS, of which the structure depends largely on their reference model (Princeton WordNet), KorLexClas 1.0 and its extended version 1.5 adopt a direct building method. They demand a considerable time and expert knowledge to establish the hierarchies of numeral classifiers and the relationships between lexical items. For the efficiency of construction as well as the reliability of KorLexClas 1.5, we use following processes: (1) to use various language resources while their cross-checking for the selection of classifier candidates; (2) to extend the list of numeral classifiers by using a shallow parsing techniques; (3) to set up the hierarchies of the numeral classifiers based on the previous linguistic studies; and (4) to determine LUB(Least Upper Bound) of the numeral classifiers in KorLexNoun 1.5. The last process provides the open list of the co-occurring nouns for KorLexClas 1.5 with the extensibility. KorLexClas 1.5 is expected to be used in a variety of NLP applications, including MT.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.740-748
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• 2016

IT and communication technologies has contributed significantly to the convenience of passengers and the financial management of stations in accordance with the task automation in the field of the urban railway system. The foundation of the above development is based on the large amounts of data from various sensors installed in railways, trains, and stations. In particular, the sensor network that is installed in the station and train has played an important role in the railway information system. The performance of AP is affected by the number of APs and their locations installed in the station. In the installation of APs in stations, the intensity of the radio wave of the AP on its underlying position is considered to determine the number and position of APs. This paper proposes a method to estimate the number of APs and their position based on the structure of the underlying station and implemented a simulator to simulate the performance of the proposed method. The implemented simulator was applied to the decision of AP installation at Busan Seomyeon station to evaluate its performance.

• Journal of the Korean Institute of Navigation
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• v.23 no.1
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• pp.75-84
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• 1999

Although many studies on modelling of port competitive situation have been conducted, both theoretical frame and methodology are still very weak. In this study, therefore, a new algorithm called ESD (Extensional System Dynamics) for the evaluation of port competition was presented, and applied to simulate port systems in northeast asia. The detailed objectives of this paper are to develop Unit fort Model by using SD(System Dynamics) method; to develop Competitive Port Model by ESD method; to perform sensitivity analysis by altering parameters, and to propose port development strategies. For these the algorithm for the evaluation of part's competition was developed in two steps. Firstly, SD method was adopted to develop the Unit Port models, and secondly HFP(Hierarchical Fuzzy Process) method was introduced to expand previous SD method. The proposed models were then developed and applied to the five ports - Pusan, Kobe, Yokohama, Kaoshiung, Keelung - with real data on each ports, and several findings were derived. Firstly, the extraction of factors for Unit Port was accomplished by consultation of experts such as research worker, professor, research fellows related to harbor, and expert group, and finally, five factor groups - location, facility, service, cargo volumes, and port charge - were obtained. Secondly, system's structure consisting of feedback loop was found easily by location of representative and detailed factors on keyword network of STGB map. Using these keyword network, feedback loop was found. Thirdly, for the target year of 2003, the simulation for Pusan port revealed that liner's number would be increased from 829 ships to 1,450 ships and container cargo volumes increased from 4.56 million TEU to 7.74 million TEU. It also revealed that because of increased liners and container cargo volumes, length of berth should be expanded from 2,162m to 4,729m. This berth expansion was resulted in the decrease of congested ship's number from 97 to 11. It was also found that port's charge had a fluctuation. Results of simulation for Kobe, Yokohama, Kaoshiung, Keelung in northeast asia were also acquired. Finally, the inter port competition models developed by ESB method were used to simulate container cargo volumes for Pusan port. The results revealed that under competitive situation container cargo volume was smaller than non-competitive situation, which means Pusan port is lack of competitive power to other ports. Developed models in this study were then applied to estimate change of container cargo volumes in competitive relation by altering several parameters. And, the results were found to be very helpful for port mangers who are in charge of planning of port development.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.468-469
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• 2018

We design CNN(convolutional neural network) which is applicable to steering control system of autonomous vehicle. CNN has been widely used in many fields, especially in image classifications. But CNN has not been applied much to the regression problem such as function approximation. This is because the input of CNN has a multidimensional data structure such as image data, which makes it is not applicable to general control systems. Recently, autonomous vehicles have been actively studied, and many techniques are required to implement autonomous vehicles. For this purpose, many researches have been studied to detect the lane by using the image through the black box mounted on the vehicle, and to get the vanishing point according to the detected lane for control the autonomous vehicle. However, in detecting the vanishing point, it is difficult to detect the vanishing point with stability due to various factors such as the external environment of the image, disappearance of the instant lane and detection of the opposite lane. In this study, we apply CNN for steering control of an autonomous vehicle using a black box image of a car.