• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.1
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• pp.79-85
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• 2017

Vehicular ad-hoc networks (VANETs) cause link disconnection problems due to the rapid speed and the frequent moving direction change of vehicles. Link disconnection in vehicle-to-vehicle communication is an important issue that must be solved because it decreases the reliability of packet forwarding. From the characteristics of VANETs, greedy forwarding protocols using the position information based on the inter-vehicle distance have gained attention. However, greedy forwarding protocols do not perform well in the urban environment where the direction of the vehicle changes greatly. It is because greedy forwarding protocols select the neighbor vehicle that is closest to the destination vehicle as the next transmission vehicle. In this paper, we propose a greedy anycast forwarding (GAF) protocol to improve the reliability of the inter-vehicle communication. The proposed GAF protocol combines the greedy forwarding scheme and the anycast forwarding method. Simulation results show that the GAF protocol can provide a better packet delivery rate than existing greedy forwarding protocols.

• Journal of Construction Engineering and Project Management
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• v.6 no.2
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• pp.30-39
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• 2016

This research presents the development of a self-governing mobile robot navigation system for indoor construction applications. This self-governing robot navigation system integrated robot control units, various positioning techniques including a dead-reckoning system, a UWB platform and motion sensors, with a BIM path planner solution. Various algorithms and error correction methods have been tested for all the employed sensors and other components to improve the positioning and navigation capability of the system. The research demonstrated that the path planner utilizing a BIM model as a navigation site map could effectively extract an efficient path for the robot, and could be executed in a real-time application for construction environments. Several navigation strategies with a mobile robot were tested with various combinations of localization sensors including wheel encoders, sonar/infrared/thermal proximity sensors, motion sensors, a digital compass, and UWB. The system successfully demonstrated the ability to plan an efficient path for robot's movement and properly navigate through the planned path to reach the specified destination in a complex indoor construction site. The findings can be adopted to several potential construction or manufacturing applications such as robotic material delivery, inspection, and onsite security.

• Journal of Ecology and Environment
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• v.38 no.2
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• pp.257-262
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• 2015

The ancient fishing methods include stone fish weir, beach seine and baulk net, but the fish catches of the stone fish weir is the most abundant. The stone fish weirs not only constitute important landscape, but also are representative of the fishery culture in Penghu, because they are fishing ground built by ancient people to take advantage of natural environment and resources. The objectives of this study is to understand the relevance of stone fish weirs in Penghu and to preserve biological diversity, as well as the value of stone fish weirs in Penghu fishery culture, and further make suggestions on the stone fish weirs. According to the present study, the marine species around the stone fish weirs tend to be diversifying, and in the future the region's economy can be revitalized by sightseeing, which may promote the ecotourism, and also volunteer tourism. In the future, stone fish weirs must be promoted as a sightseeing destination. Also, by taking into consideration the experience of the Jibei stone weir protection team, the local communities of Penghu can have their own protection team to revitalize the stone fish weirs for sustainable operation and management.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.4
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• pp.57-65
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• 2010

Application of WBAN technology in medical field facilitates the prevention of diseases by collecting the vital signs remotely. It also enables to prevent the accidental emergency situation in advance plus long-tem monitoring of patients with chronic diseases such as heart diseases, hypertension, or the elderly and infirm. For emergency patients, major vital signal information collected by the 'Sensing' should have the top priority and such information should be transferred as promptly as possible without competition. In addition, when an emergency occurs to a patient, a priority mechanism is necessitated for a urgent message to get through to the final destination. However, LR-WPAN IEEE 802.15.4 technology does not consider such emergency message handling features. To deal with aforementioned issues, the IEEE 802.15.4 super frame protocol structure has been designed for stable transfer of emergency information in WBAN environment in this study, and alternation to super frame structures have been made, allowing GTS(Guaranteed Time Slot) can be used first at CFP (Contention Free Period) by reserving the resources in advance and prioritize the emergency signals. NS-2 has been utilized for the performance test and analysis.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.4
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• pp.117-130
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• 2010

Paper is on defense for so-called internet crisis, the attack of DDoS (Distributed Denial of Service) which was targeted to the central government ministries, financial sector, and portal sites of chief counties including Korea on June 7th, 2009 as its start. By conducting attack with various DDoS attacking methods in the lab environment and dividing networks targeted by the attack by layers, this paper records and analyzes the chief information for attack, destination information of packets, defense policy setting, and the flow of packet attack with the subjects of the networks separated. This study suggests CFC system using multiple firewalls applying defense policy corresponding to the target layer for ultimate attack and tests it according to the result of analyzing the attack packet information and its amount, log analysis, access recording port, and MAC and IT information, etc. by layers. This article is meaningful in that it analyzes the attack by layers, establishes firewall policy for protecting each layer, and secures accurate mechanism for detect and defense.

• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.397-408
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• 2015

Purpose: Express mail service(EMS) supplied by 'Korea POST'is an international postal service which brings letters, documents and parcels to a destination abroad in the fastest and safest way. This service is in a tough competition with global companies such as TNT, FedEx, DHL or UPS. To build an effective strategy for being competitive, an intensive study on EMS service quality should be accomplished from a customer's perspective. Methods: Kano model and improvement gap analysis are used to categorize and prioritize EMS service quality attributes. A 5-point Lickert scale is employed to apply the Kano model and improvement gap analysis. Each quality attribute can be classified as weak in comparison with competitors, critical for improvement, or potentially competitive. Results: Price, on-time delivery and delivery quality are to be kept as is; fast delivery, parking convenience and staff expertise can be potentially competitive; and the other attributes are considered to be critical for improvement. Conclusions: Fast reimbursement and proper compensation when shipping items are lost or damaged are to be improved with high priority. Efforts to secure fast delivery, parking convenience and staff expertise are needed to be competitive in the future.

• Journal of the Korean Society of Food Culture
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• v.30 no.4
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• pp.413-421
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• 2015

A travel destination offers a form of novelty to the traveler since it can provide experiences that are not of the everyday variety. Therefore, a search for novelty is important as a motivation factor when planning leisure trips and vacation activities and to identify travel market segments. This study aimed to examine the differences in demographic characteristics, travel style, and preferred food-related activities in accordance with the level of tourists' novelty seeking. This study investigated potential tourists using a self-administered questionnaire survey, which resulted in 300 usable questionnaires. The respondents of this study were classified into two groups according to their level of novelty seeking: Active novelty-seeking group and Passive novelty-seeking group. These two groups were significantly different with respect to demographic characteristics, travel style, and preference of food-related-activity experience. The results show that the Active novelty-seeking group tended to have a higher proportion of females and specialized jobs, a higher level of monthly income and education, more frequent travel, and preference for food-related activity experience than other groups. The result of this study will be helpful for the tourist industry, which needs to develop culinary and food-related experience tour programs and travel market segments.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.4
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• pp.47-60
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• 2015

In this paper, we propose a simple and useful method using a port role to visualize the network attacks. The port role defines the behavior of the port from the source and destination port number of network session. Based on the port role, the port provides the brief security features of each node as an attacker, a victim, a server, and a normal host. We have automatically classified and identified the type of node based on the port role and security features. We detected and visualized the network attacks using these features of the node by the port role. In addition, we are intended to solve the problems with existing visualization technologies which are the reflection problem caused an undirected network session and the problem caused decreasing of distinct appearance when occurs a large amount of the sessions. The proposed method monitors anomalies occurring in an entire network and displays detailed information of the attacker, victim, server, and hosts. In addition, by providing a categorized analysis of network attacks, this method can more precisely detect and distinguish them from normal sessions.

• Journal of the Korea Safety Management & Science
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• v.19 no.2
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• pp.147-157
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• 2017

The tourism experience factor is an essential source of competitive advantage in the tourism industry and is an important factor for predicting future tourism behavior. Tourism experience elements can be composed of areas of education, entertainment, aesthetics and deviance (Pine and Gilmore, 1998). This study examines the effect of tourist experience factors on tourist loyalty and it is meaningful to see if the experiential economic theory of Pine and Gilmore (1999) is applicable. In order to achieve the purpose of this study, we conducted a questionnaire survey on tourists using experiential tourism factors. As a result, it was found that recreational experiential factors had a significant effect on memory. Memory has a significant effect on both visitor satisfaction and tourist loyalty. This study has academic significance because it focuses on the tourism experience factor which is the core of experiential economic theory. Practical significance is that a lot of experiential contents should be found in order to better match the tourist experience factor to the requirements of visitors to the tourist site. As a result, it is expected to generate revenue and improve its competitiveness.

• Journal of Internet Computing and Services
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• v.22 no.6
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• pp.1-8
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• 2021

With the rapid growth of intelligent devices and communication technologies, 5G network environment has become more heterogeneous and complex in terms of service management and orchestration. 5G architecture requires supportive technologies to handle the existing challenges for improving the Quality of Service (QoS) and the Quality of Experience (QoE) performances. Among many challenges, traffic steering is one of the key elements which requires critically developing an optimal solution for smart guidance, control, and reliable system. Mobile edge computing (MEC), software-defined networking (SDN), network functions virtualization (NFV), and deep learning (DL) play essential roles to complementary develop a flexible computation and extensible flow rules management in this potential aspect. In this proposed system, an accurate flow recommendation, a centralized control, and a reliable distributed connectivity based on the inspection of packet condition are provided. With the system deployment, the packet is classified separately and recommended to request from the optimal destination with matched preferences and conditions. To evaluate the proposed scheme outperformance, a network simulator software was used to conduct and capture the end-to-end QoS performance metrics. SDN flow rules installation was experimented to illustrate the post control function corresponding to DL-based output. The intelligent steering for network communication traffic is cooperatively configured in SDN controller and NFV-orchestrator to lead a variety of beneficial factors for improving massive real-time Internet of Things (IoT) performance.