• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.7
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• pp.1831-1853
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• 2012

By sending periodically short bursts of traffic to reduce legit transmission control protocol (TCP) traffic, the low-rate denial of service (LDoS) attacks are hard to be detected and may endanger covertly a network for a long period. Traditionally, LDoS detecting methods mainly concentrate on the attack stream with feature matching, and only a limited number of attack patterns can be detected off-line with high cost. Recent researches divert focus from the attack stream to the traffic anomalies induced by LDoS attacks, which can detect more kinds of attacks with higher efficiency. However, the limited number of abnormal characteristics and the inadequacy of judgment rules may cause wrong decision in some particular situations. In this paper, we address the problem of detecting LDoS attacks and present a scheme based on the fluctuant features of legit TCP and acknowledgment (ACK) traffic. In the scheme, we define judgment criteria which used to identify LDoS attacks in real time at an optimal detection cost. We evaluate the performance of our strategy in real-world network topologies. Simulations results clearly demonstrate the superiority of the method proposed in detecting LDoS attacks.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.253-256
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• 2005

The use of satellite remote sensing in maritime safety and security can aid in the detection of illegal fishing activities and provide more efficient use of limited aircraft or patrol craft resources. In the area of vessel traffic monitoring for commercial vessels, Vessel Traffic Service (VTS) which use the ground-based radar system have some difficulties in detecting moving ships due to the limited detection range. A virtual vessel traffic control system is introduced to contribute to prevent a marine accident such as collision and stranding from happening. Existing VTS has its limit. The virtual vessel traffic control system consists of both data acquisition by satellite remote sensing and a simulation of traffic environment stress based on the satellite data, remotely sensed data. And it could be used to provide timely and detailed information about the marine safety, including the location, speed and direction of ships, and help us operate vessels safely and efficiently. If environmental stress values are simulated for the ship information derived from satellite data, proper actions can be taken to prevent accidents. Since optical sensor has a high spatial resolution, JERS satellite data are used to track ships and extract their information. We present an algorithm of automatic identification of ship size and velocity. This paper lastly introduce the field testing results of ship detection by RADARSAT SAR imagery, and propose a new approach for a Vessel Monitoring System(VMS), including VTS, and SAR combination service.

• Culinary science and hospitality research
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• v.8 no.1
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• pp.71-94
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• 2002

The food service industry has grown up without an affection of economic collapse, and its kinds are being diversified and focused on many different aspects from physical taste to many other elements such as atmosphere, service quality, sanitation and etc.. Now it appeals to even familiarity. These Facts are well ref looted to Family Restaurant which has not been very popular so far, but now it takes its space in the market, and its management system is being introduced to other countries. The purpose of this study is to see how to satisfy them to make maximum business profit, and one possibility is "incentive". To accomplish research, theoretical and practical studies have been done and surveys have taken placed for substantial studies. The subjects were limited to employees in Family Restaurant in Seoul from February 20th to March 20th, 2001. Data, reliableness, and propriety were analyzed by SAS(Statistical Analyzed System). Sampling mode was randomness, and validation mode was limited to 223 papers. The followings are the results of this analysis First, Satisfaction of incentive were made by stability, impartiality and suitability regardless difference on companies, ages, departments, and authority of an employees. Second, Satisfaction on incentive for employees in Family Restaurants were not well received. Although these necessary demand, there is not yet incentive system operation to most of business. Especially, it is not even studied on Family Restaurants. This study should have been studied on more customers and spotted employees to be objective. It is strongly recommended to do this study without limitation and further studies is considered on this subjects.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.10
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• pp.1003-1008
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• 2016

Recently hospitals have divided into many divisions, specialized the medical service, and shown organic cooperation, all to provide patients with various and high quality medical service. They have also showed improvement in information protection by introducing an information protection system to regulate the access to patients' medical and personal information. The purpose of this paper is to present a case study to implement of a limited hospital medical information system that can regulate the access to medical information. For this, a router-based virtual network applying an ACL(: Access Control List) to regulate access to information was made using a packet tracer.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.1
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• pp.77-88
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• 1997

Fieldbus is the lowest level communication network in factory automation and process control systems. Performance of factory automation and process control systems is directly affected by the data delay induced by network traffic. Data generated from several distributed field devices can be largely divided into three categories: sporadic real-time, periodic real-time and non real-time data. Since these data share one fieldbus network medium, the limited bandwidth of a fieldbus network must be appropriately allocated to the sporadic real-time, periodic real-time and non real-time traffic. This paper introduces a new fieldbus design scheme which allocates the limited bandwidth of fieldbus network to several different kinds of traffic. The design scheme introduced in this study not only satisfies the performance requirements of application systems interconnected into the fieldbus but also fully utilizes the network resources. The design scheme introduced in this study can be applicable to cyclic service protocols operated under single-service discipline. The bandwidth allocation scheme introduced in this study is verified using a discrete-event/continuous-time simulation experiment.

• Korean Institute of Interior Design Journal
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• v.20 no.4
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• pp.183-190
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• 2011

Lately majority of churches have preferred to enlarge their worship area to both horizontal and vertical axis. According to expand their area which brings more devotees to the limited service area. Transform from a small church into a large church is no longer unprecedented issue in South Korea. As the size of church getting bigger, many unexpected issues become matters. One of the significant problem is that the number of people have experienced either fall a sleep or feel a doziness during their service period. Due to the limited condition for the specific building type such as religion facility(church), IAQ improvements is seriously concerned. Therefore, we are going to examine by using simulation tool, CF, a difference of ventilation efficiency about the location and number of windows, and find the best way of the ventilation efficiency in a multi-stories type church by changing the exhaust pipes location and size. Furthermore, in this thesis, by changing a ceiling height from the existing building to confirm that $CO_2$ have been satisfied for both the ventilation efficiency and IAQ.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.3
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• pp.119-127
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• 2019

COsmicheskaya Sisteyama Poiska Avariynich Sudov Search and Rescue Satellite-Aided Tracking (COSPAS-SARSAT) is an international communication support program to perform search and rescue (SAR) operations in emergency situations by using satellite signals relayed from a beacon. The legacy COSPAS-SARSAT was originally composed of low altitude and geostationary Earth orbit satellites; thus, a limited number of directional dish antennas was sufficient to cover the limited number of visible satellites at the local user terminal. However, the second generation COSPAS-SARSAT newly added the medium Earth orbit satellites, e.g., Global Navigation Satellite Systems (GNSS) to the existing system, so that the number of visible satellites increase dramatically, and the system upgrade to cover all the visible satellites is foreseen. The additional use of planned Korea Positioning System (KPS) to existing GNSS is envisaged to provide a better performance of their SAR service. This paper presents the benefits of the additional use of KPS together with the phased array antennas at the local user terminal of the COSPAS-SARSAT. This is to effectively response to the increase of the number of visible satellites. Numerical simulation is included to evaluate the performance improvement of COSPAS-SARSAT in terms of the number of visible satellites, geometry between satellites and user, and position estimation accuracy.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1166-1169
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• 2009

Bridges are exposed to very severe environment and experience, as service life increased, elevated traffic load and traffic flow, in addition to natural disasters. In comparing to other road structures, bridges may cause more significant damage, such as human-involved accidents, to the society in the event of collapse. A certain level of service shall be necessarily secured to assure the minimum safety of users. The cost for manage and preserve bridges will increase gradually and more restrictions will be loaded to efficiently distribute the limited resources, such as monetary budget and human resource etc. In order to enhance performance and serviceability of bridges with the limited resource, asset management technique has been applied into the bridge management system, which capitalizes the road infrastructures including bridges and assess them in accordance with the government finance report. In the application of asset management, there must be a tool for assess the performance of bridges and this study introduces the basic information on the definition and role of performance measures for asset management for bridges. This research suggests future development direction of performance measure for asset management for bridges in Korea.

• Korean Journal of Social Welfare
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• v.43
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• pp.270-298
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• 2000

Government provides financial support to the 74 Home help service centers, 36 Day care service centers, and 18 Short stay service centers for the elderly. The number of service centers that receive financial support from the government is far less to meet the potential demand for the community care services. This paper applies cost-benefit analysis to evaluate the net social benefit of the services provided by the 3 types of the community care service centers sponsored by the government to justify the expansion of the government support. The benefit is calculated as community care services are provided privately in the market without financial support from the government. The potential market price is regarded as the benefit or value provided to the elderly. The price levels that potential users are willing to pay for these services are surveyed in the Census for the Elderly by the KIHASA, 1998. The market prices for the community services are generated by equating limited amount of service supply, as in number of users in one year in 3 types of community care service centers, and potential demand for the services. Market prices are multiplied to the number of users of 3 types of community centers to get the total benefit. Total operating cost of the community care service centers is regarded as cost. According to the cost-benefit analysis, Home-help service centers generated net social benefit of 137 billion Won, Day Care service centers generated 15 billion Won, and Short stay service centers generated 6 billion Won. Significant amount of net social benefit indicates that government should increase level of financial support to these service centers.

• Journal of Korean Society for Quality Management
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• v.40 no.4
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• pp.513-530
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• 2012

Purpose: The requirement for legal services is going up by modern people living in the era of complexity and variety who want to resolve legal conflicts between individuals and improve their personal rights. Methods: In this study, we used both literature and empirical researches to achieve our goals. In literature research, concept of service quality, method of measuring service quality, and dimension of service quality were explored, relationship among service quality, customer satisfaction, and customer loyalty and hypothesis was made based on the above, and tested. To test the conceptual framework, structural equation modeling (SEM) has been used to analyze the data collected from 252 customers of Judicial Agents's Service. Results: This result is not consistent with that of advanced study; it was found that service has significant influence on customer trust, and the trust also has significant influence on customer satisfaction and loyalty. Conclusion: This study has limitations in terms of restricted service sectors and measuring methods. For this reason, the followings are needed to be considered for interpretation and generalization of the study results. We believe that further studies are needed to investigate other service areas as well as legal service at the same time, and study target which is limited to Gangwon Province needs to be expanded for more accurate investigation. In addition, in-depth follow-up study should be proceeded considering variables such as customer value, conversion cost, and image of service providers.