• Journal of Korean Society of Transportation
• /
• v.18 no.5
• /
• pp.83-97
• /
• 2000

The traffic management schemes through traffic signal control and information provision could be effective when the link-level data and trip-level data were used simultaneously in analysis Procedures. But, because the trip-level data. such as origin, destination and departure time, can not be obtained through the existing surveillance systems directly. It is needed to estimate it using the link-level data which can be obtained easily. Therefore the objective of this study is to develop the model to estimate O-D demand using only the link flows in highway network as a real time. The methodological approaches in this study are kalman filer, least-square method and normalized least-square method. The kalman filter is developed in the basis of the bayesian update. The normalized least-square method is developed in the basis of the least-square method and the natural constraint equation. These three models were experimented using two kinds of simulated data. The one has two abrupt changing Patterns in traffic flow rates The other is a 24 hours data that has three Peak times in a day Among these models, kalman filer has Produced more accurate and adaptive results than others. Therefore it is seemed that this model could be used in traffic demand management. control, travel time forecasting and dynamic assignment, and so forth.

• Korean Business Review
• /
• v.22 no.2
• /
• pp.139-156
• /
• 2009

Mountain tourism is regarded as an important inbound tourist destination for the whole world. The Himalayan Mountains are house of world's highest peaks that includes over 100 mountains exceeding 8,500 meters. However limited dimension of visitors constraints and motivation has been reported about the high altitude mountain. This research work permits the identification of some of the motivation and constraints related to the decision making of tourism in high altitude mountains. The study was conducted in Korea, Indian state (Sikkim), and Nepal (Kathmandu) due to the popularity and the major destination for mountain tourism. A set of 9 motive, 45 motivation items and 40 constraints were initially generated from a review of research pertaining to visitor motivation and constraints. They were considered to be the most appropriate for measuring visitors motivation and constraints for experiencing high altitude mountain tourism. Validity of dimensionality and inter correlation was evaluated by factor analysis investigation and analysis of obtained data revealed that constraints of Korean are significantly higher than Indian and other inbound tourist. Among the major constraints structural constraints were recorded higher for Indian, Korean and other visitors. Similarly, motives of different visitors varied significantly. This analysis also revealed that Korean motives for travelling were influenced by health and pleasure, whereas, Indian and others motives were mostly related to knowledge seeking and adventure. The environmental importance were given priority by all the countries. The purpose of this study includes; (1) To identify the motives of visitors in high altitude destinations. (2) To analysis the major motivation factor for the altitude tourism. (3) To report the major constraints of visitors travelling to the high altitude. (4) To study whether the strength of motivation help to overcome the constraints.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.10
• /
• pp.4678-4702
• /
• 2018

Traffic Matrix estimation has always caught attention from researchers for better network management and future planning. With the advent of high traffic loads due to Cloud Computing platforms and Software Defined Networking based tunable routing and traffic management algorithms on the Internet, it is more necessary as ever to be able to predict current and future traffic volumes on the network. For large networks such origin-destination traffic prediction problem takes the form of a large under- constrained and under-determined system of equations with a dynamic measurement matrix. Previously, the researchers had relied on the assumption that the measurement (routing) matrix is stationary due to which the schemes are not suitable for modern software defined networks. In this work, we present our Compressed Sensing with Dynamic Model Estimation (CS-DME) architecture suitable for modern software defined networks. Our main contributions are: (1) we formulate an approach in which measurement matrix in the compressed sensing scheme can be accurately and dynamically estimated through a reformulation of the problem based on traffic demands. (2) We show that the problem formulation using a dynamic measurement matrix based on instantaneous traffic demands may be used instead of a stationary binary routing matrix which is more suitable to modern Software Defined Networks that are constantly evolving in terms of routing by inspection of its Eigen Spectrum using two real world datasets. (3) We also show that linking this compressed measurement matrix dynamically with the measured parameters can lead to acceptable estimation of Origin Destination (OD) Traffic flows with marginally poor results with other state-of-art schemes relying on fixed measurement matrices. (4) Furthermore, using this compressed reformulated problem, a new strategy for selection of vantage points for most efficient traffic matrix estimation is also presented through a secondary compression technique based on subset of link measurements. Experimental evaluation of proposed technique using real world datasets Abilene and GEANT shows that the technique is practical to be used in modern software defined networks. Further, the performance of the scheme is compared with recent state of the art techniques proposed in research literature.

• Journal of Sasang Constitutional Medicine
• /
• v.23 no.1
• /
• pp.115-124
• /
• 2011

1. Objectives : This study aimed to provide practical insights on the development of traditional Korean medical tourism and maximize the satisfaction of foreign patients. The main objectives of this study were also to evaluate Sasang Constitutional Medicine(S.C.M.) diagnosis cost from foreigners' perspectives. 2. Methods : For this study, the data were collected from tourists to Korea between January 3, 2010 to February 20, 2010. The sample used in this study was mainly composed of Japanese, Chines and US/Canada, because they are the major national visitor origin group to Korea. The primary data were collected by questionnaire survey using a standardized instrument with a convenience sampling procedure, and efforts of the interviews involved an on-site, self-administrated questionnaire to those sitting or visiting tourist attractions. The total size of the sample was 276 of which 275 showed no missing value against the factors needed for final analysis and were for analysis as an effective sample. SPSS 13.0 for window was used to analyze the collected data on which descriptive statistics and the Limited Dependent(LIMDEP) 8.0 program was used in estimating the willingness-to-pay(WTP) for traditional Korean medical tourism through the Contingent Valuation Method(CVM). A dichotomous choice question form of a CVM was applied to estimating the value. 3. Results and Conclusion: 1. There was significant statistical relationship between attributes when considering medical tourism destination and socio-demographic profiles such as age group, nationality, educational level and occupation. 2. In the level of recognition on Korean medicine, north Americans showed low level of recognition compared to other nationalities. In addition, in terms of age group, 20's and 30's showed low level of recognition on Korean medicine, 3. In relation to the level of interest on Korean medicine, Japanese respondents had higher interesting level on Korean medicine. Also singles had higher level of interest. 4. Regarding preferred Korean medical treatment program, there found significant statistical relationship between Korean medical treatment program and socio-demographic characteristics. 5. The estimating result of the logit model showed that the variables affecting the WTP for Sasang Constitutional medicine diagnosis were offered price and potential ability of medical tourism destination. 6. In relation to WTP for Sasang Constitutional medicine diagnosis, Japanese respondents showed a WTP of USD 62.69 and Chinese respondents showed USD 57.09. On the other hands, respondents from north America and other countries showed a WTP of USD 65.50. In conclusion, from this study, the results found that the opportunities in tradition Korean medical tourism are immense and the possible rewards are numerous. It is time to continue to promote 'Sasang Constitutional medicine' and make the Korean medical tourism programs considering on nationalities, age group, gender and WTP.

• The KIPS Transactions:PartC
• /
• v.12C no.6 s.102
• /
• pp.847-854
• /
• 2005

Since the propagation speed of the Internet worms is quite fast, worm detection in early propagation stage is very important for reducing the damage. Virus throttling technique, one of many early worm detection techniques, detects the Internet worm propagation by limiting the connection requests within a certain ratio.[6, 7] The typical throttling technique increases the possibility of false detection by treating destination IP addresses independently in their delay queue managements. In addition, it uses a simple decision strategy that determines a worn intrusion if the delay queue is overflown. This paper proposes a two dimensional delay queue management technique in which the sessions with the same destination IP are linked and thus a IP is not stored more than once. The virus throttling technique with the proposed delay queue management can reduce the possibility of false worm detection, compared with the typical throttling since the proposed technique never counts the number of a IP more than once when it chicks the length of delay queue. Moreover, this paper proposes a worm detection algorithm based on weighted average queue length for reducing worm detection time and the number of worm packets, without increasing the length of delay queue. Through deep experiments, it is verified that the proposed technique taking account of the length of past delay queue as well as current delay queue forecasts the worn propagation earlier than the typical iuぉ throttling techniques do.

• Korean Journal of Environment and Ecology
• /
• v.24 no.2
• /
• pp.130-138
• /
• 2010

The purpose of this study is the investigation and analysis of information on the conservation and the sustainable use of coastal wetlands based on the awareness of local residents in Suncheon Bay and Taeanhaean National Park. To accomplish the purpose of study, a questionnaire survey was chosen and the 98 valid samples(38 from Taeanhaean National Park and 60 from Suncheon Bay) among them were analyzed. The results are summarized as follows: The degree of the satisfaction on the natural environment is alike between Taeanhaean National Park and Suncheon-bay area. This is accorded with the order of the goodness of natural environment. The order for the degree of the satisfaction on the living environment is same as the order for the satisfaction degree on the natural environment. The residents of two regions are not satisfied with the socio·economic environment. The local resident of Suncheon Bay and Taeanhaean National Park Area where natural environment is well-conserved, prefer conservation to development of the region. These results show the following consideration for the ideal method of management for the conservation and sustainable development of coastal wetlands. In case of Suncheon Bay area, where the condition the natural environment is well conserved, should be managed with the minimum development with maintenance of the current state must be driven. In case of Taeanhaean National Park Area, where the condition of the natural environment is well conserved and the development potential exists, such as sustainable development and ecotourism destination the development that is in harmony with the nature must to be driven.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.8
• /
• pp.3551-3567
• /
• 2016

The Low Earth Orbit satellite network has the unique characteristics of the non-uniform and time-variant traffic load distribution, which often causes severe link congestion and thus results in poor performance for delay-sensitive flows, especially when the network is heavily loaded. To solve this problem, a novel adaptive routing algorithm, referred to as the delay-oriented adaptive routing algorithm (DOAR), is proposed. Different from current reactive schemes, DOAR employs Destination-Sequenced Distance-Vector (DSDV) routing algorithm, which is a proactive scheme. DSDV is extended to a multipath QoS version to generate alternative routes in active with real-time delay metric, which leads to two significant advantages. First, the flows can be timely and accurately detected for route adjustment. Second, it enables fast, flexible, and optimized QoS matching between the alternative routes and adjustment requiring flows and meanwhile avoids delay growth caused by increased hop number and diffused congestion range. In addition, a retrospective route adjustment requesting scheme is designed in DOAR to enlarge the alternative routes set in the severe congestion state in a large area. Simulation result suggests that DOAR performs better than typical adaptive routing algorithms in terms of the throughput and the delay in a variety of traffic intensity.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.08a
• /
• pp.167-176
• /
• 2004

The authors have newly developed the “Port Traffic Management System (PTMS)”. The PTMS provides each ship with the detailed planned routes of all the ships entering/leaving the port. This system also has a function to predict the encounter situations between own ship and other ships in the future. Based on information of the present positions, speeds and planned routes of the own ship and other ships, it is possible to predict when and where the own ship will have dangerous encounters with other ships in the future. The software of PTMS was developed from 2001. Then onboard experiments using small training ships equipped with actual AIS were performed in June 2003. From the results of these onboard experiments, the usefulness of PTMS was clarified. In addition to these onboard experiments, the effectiveness of PTMS was confirmed by comprehensive simulator experiments. In the simulator experiments, captains/pilot maneuvered a training ship/container ship in congested waters using PTMS. [t was assumed that all ships have PTMS and send their planned routes. After the simulator experiments, captains/pilot suggested that it is very beneficial if the optimal route of own ship can be automatically calculated. In response to this suggestion, software to calculate the optimal route of own ship using Dynamic Programming was developed. This software calculates the minimum time route from the present position to the destination keeping the danger of collision against other ships under predetermined level. From the result of calculations for multi-encounter situations, it was confirmed that the developed software can provide safe and time-saving route.

• Journal of Internet Computing and Services
• /
• v.8 no.6
• /
• pp.1-8
• /
• 2007

The Mobile Ad-hoc network does environmental information which an individual collects in nodes which are many as the kernel of the USN technology based on the radio communication. And it is the latest network description delivering critical data to the destination location desiring through a multi-hop. Recently, the Ad-hoc network relative technique development and service are activated. But the security function implementation including an authentication and encoding about the transmitted packets, and etc, is wirelessly the insufficient situation on the Ad-hoc network. This paper provides the security service of key exchange, key management. entity authentication, data enciphering, and etc on the Mobile Ad-hoc network. It implements with the Ad-hoc network security management server system design which processes the security protocol specialized in the Ad-hoc network and which it manages.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.5B
• /
• pp.455-462
• /
• 2009

In this paper, we propose a buffer management scheme for decreasing the packet loss due to buffer overflow and improving the packet fairness between nodes in IEEE 802.11 based multi-hop mesh networks. In the proposed scheme, each mesh router that is an intermediate node receives fairly packet sent from neighboring mesh routers and mobile nodes, and it improves the reception ratio of multi-hop traffic of neighboring mesh routers. Therefore, the proposed scheme can reduce transmission delay and energy consumption. In order to improving the packet loss and the packet fairness, the proposed scheme uses the modified RTS/CTS under the IEEE 802.11 MAC protocol and reduces the packet loss by recognizing the packet size to send to the destination in advance. By using the simulation, we evaluated the proposed scheme in terms of the packet loss ratio and the number of received packet in each mesh router, and compare it to a traditional scheme.