• Journal of Yeungnam Medical Science
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• v.9 no.2
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• pp.302-311
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• 1992

Talus is a important structure of the ankle joint and its function is critical for ambulation and weight bearing. The talus fracture is rare, but the complications of fracture and dislocation are serious and resulting in avascular necrosis, osteoarthritis. So its treatment is carefully considered at initial status. Authors reviewed 11 cases of fracture and dislocation of the talus treated at Yeungnam university hospital from 1984 to 1991. The longest follow up was 8 years and shortest, 1 year. The results were as follows. 1. There were all males, the average age was 30 years old. 2. The most common cause was fall down(8 cases), and next traffic accident(2cases), sports injury(1 case). 3. According to Marti-Weber classification, 1 cases was type I, 1 in type II, 4 in type III and 5 in type IV. 4. The method of treatment were open reduction and internal fixation in 6 cases, the others were closed reduction in 5 cases. 5. Final results(by Hawkins grading system) were as follows, 3 cases were excellent, 4 cases were good, 1 case was fair and 3 cases were poor. 6. Complications were AVN in 2 cases, degenerative arthritis in 8 cases, malunion in 1 case. 7. The range of motion of the ankle joint was relatively preserved(74%), but in the subtalar joint it was decreased(43%).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7292-7301
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• 2014

With the development of IT Info-Communications technology, the vehicle with a combination of wireless-communication technology has resulted in significant research into the convergence of the component of existing traffic with information, electronics and communication technology. Intelligent Vehicle Communication is a Machine-to-Machine (M2M) concept of the Vehicle-to-Vehicle. The Vehicle-to-Infrastructure communication consists of safety and the ease of transportation. Security technologies must precede the effective Intelligent Vehicle Communication Structure, unlike the existing internet environment, where high-speed vehicle communication is with the security threats of a wireless communication environment and can receive unusual vehicle messages. In this paper, the Vehicle Identification number between the V2I and the secure message communication protocol was proposed using hash functions and a time stamp, and the validity of the vehicle was assessed. The proposed system was the performance evaluation section compared to the conventional technique at a rate VPKI aspect showed an approximate 44% reduction. The safety, including authentication, confidentiality, and privacy threats, were analyzed.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.5
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• pp.265-273
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• 2002

With the explosive growth of WWW traffic, there is an increasing demand for the high performance Web servers to provide a stable Web service to users. The cluster-based Web server is a solution to core with the heavy access from users, easily scaling the server according to the loads. In the cluster-based Web sewer, a back-end node may not be able to serve some HTTP requests directly because it does not have the requested contents in its main memory. In this case, the back-end node has to retrieve the requested contents from its local disk or other back-end nodes in the cluster. To reduce service latency, we introduce a new prefetch scheme. The back-end nodes predict the next HTTP requests and prefetch the contents of predicted requests before the next requests arrive. We develop three prefetch algorithms bated on some useful information gathered from many clients'HTTP requests. Through trace-driven simulation, the service latency of the prefetch scheme is reduced by 10 ~ 25% as compared with no prefetch scheme. Among the proposed prefetch algorithms, Time and Access Probability-based Prefetch (TAP2) algorithm, which uses the access probability and the inter-reference time of Web object, shows the best performance.

• Journal of Distribution Science
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• v.4 no.1
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• pp.53-78
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• 2006

We call this world network society. Logistics is one of important network systems which connect people, materials and information. The World Economy Conditions of 21st Century has been Changed so rapidly. These Changes are more conspicuous in Northeast Asia than other Regions. China, North Korea and Russia have reformed their Economical and Social Systems, which enlarged the Trade Volume and Traffic Demand in this Area and between Europe. The Railway System Crossing the Eurasia Continent, such as TSR(Trans Siberian Railway), TCR(Trans China Railway), TMR(Trans Manchuria Railway), TMGR(Trans Mongolia Railway) and TKR(Trans Korea Railway), have been becoming very important to enhance the International Transportation efficiency and to connect each continents by International Railways. This Paper investigated and surveyed the logistical Environments surrounding this Korea Peninsula. And concerned with the Crossing Continents Railway, TSR,TCR(TMR, TMGR), TKR, operating Conditions and Tasks that must be considered and solved were also investigated. Especially the Current Logistical Conditions of China, Russia, and North Korea and their Problems were surveyed. And the SWOT of these Railways were analyzed and compared. The Visions and Goals of these Inter-Continental Railways were suggested in terms of their Rationalization of Operations and efficient Connections among many Countries. Not only the Policies and Strategies/Tactics which should be considered but also and Many detail countermeasures which should be introduced and adopted were suggested.

• Journal of Navigation and Port Research
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• v.31 no.6
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• pp.537-543
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• 2007

It's an important part to calculate the weights between criterions and to aggregate the decision inputs in a MCDM(Multi criterion decision making) This paper presents a method for aggregation cf decision inputs and application to the MCDM. We incorporate the fuzzy set theory and the basic nature of subjectivity due to ambiguity to achieve a flexible decision approach suitable for uncertain and fuzzy environments. To obtain the scoring that corresponds to the best alternative or the ranking of the alternatives, we need to use a total order for the fuzzy numbers involved in the problem. In this article, we consider a definition of such a total order, which is based on two subjective aspects: the degree of optimism/pessimism reflected with the ordered weighted averaging(OWA) oprators. A numerical example, expecially location analysis for anchorage area, is given to illustrate the approach.

• Journal of Navigation and Port Research
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• v.41 no.3
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• pp.137-148
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• 2017

Port service level is a metric of competitiveness among ports for the operating/managing bodies such as the terminal operation company (TOC), Port Authority, or the government, and is used as an important indicator for shipping companies and freight haulers when selecting a port. Considering the importance of metrics, we developed software to objectively define and manage six important service indicators exclusive to container and bulk terminals including: berth occupancy rate, ship's waiting ratio, berth throughput, number of berths, average number of vessels waiting, and average waiting time. We computed the six service indicators utilizing berth 1 through berth 5 in the container terminals and berth 1 through berth 4 in the bulk terminals. The software model allows easy computation of expected ship's waiting ratio over berth occupancy rate, berth throughput, counts of berth, average number of vessels waiting and average waiting time. Further, the software allows prediction of yearly throughput by utilizing a ship's waiting ratio and other productivity indicators and making calculations based on arrival patterns of ship traffic. As a result, a TOC is able to make strategic decisions on the trade-offs in the optimal operating level of the facility with better predictors of the service factors (ship's waiting ratio) and productivity factors (yearly throughput). Successful implementation of the software would attract more shipping companies and shippers and maximize TOC profits.

• The KIPS Transactions:PartA
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• v.12A no.7 s.97
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• pp.627-636
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• 2005

This paper presents a PC cluster-based distributed video on demand (VOD) server that minimizes the load of the interconnection network by adopting channel bonding-based MVIA and the interval cache algorithm Video data is distributed to the disks of each server node of the distributed VOD server and each server node receives the data through the interconnection network and sends it to clients. The load of the interconnection network increases because of the large volume of video data transferred. We adopt two techniques to reduce the load of the interconnection network. First, an Msupporting channel bonding technique is adopted for the interconnection network. n which is a user-level communication protocol that reduces the overhead of the TCP/IP protocol in cluster systems, minimizes the time spent in communicating. We increase the bandwidth of the interconnection network using the channel bonding technique with MThe channel bonding technique expands the bandwidth by sending data concurrently through multiple network cards. Second, the interval cache reduces traffic on the interconnection network by caching the video data transferred from the remote disks in main memory Experiments using the distributed VOD server of this paper showed a maximum performance improvement of $30\%$ compared with a distributed VOD server without channel bonding-based MVIA and the interval cache, when used with a four-node PC cluster.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.147-154
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• 2006

The certificate status validation mechanism is a critical component of a public key infrastructure based on certificate system. The most generally mechanisms used these days are the use of the certificate revocation list and the real-time certificate status protocol. But the certificate revocation list can not give the real-time certificate status because the certificate is being delivered periodically, and the real-time certificate status protocol method will generate a concentrated load to the server because the protocol in the central server will be accessed whenever a certification is necessary. It will also take a long time to validate the certificate because each trade has to send mass information through the network. This paper will present that real-time validation is guaranteed as the real-time certificate status protocol method and the traffic congestion in the network Is reduced in a way that the certification would be requested using the user information hash value and would be validated using the user information kept in the certification authorities and the service providers. Based on the this study, we suggest a real-time certificate status validation mechanism which can reduce the certificate status validation time using the signed user information hash value. And we confirm speed of certificate status verification faster than existing CRL(Certificate Revocation List) and OCSP(Online Certificate Status Protocol) method by test.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9A
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• pp.737-748
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• 2005

Two flexible admission control schemes for integrated voice and stream-type data services are proposed in DS-CDMA systems. Most Previous studies on admission control have focused on integration of short, bursty Packet-type data services and conventional voice services. However, stream-type data services with a relatively long service holding time are expected to be a considerable portion of data traffic in future generation cellular systems. Scheme I is a basic scheme that accommodates both voice and data services with full bandwidth. However, voice services are given priority over data services using the duration difference between the holding times for these services. Scheme ll uses a different method to efficiently give priority to voice services over stream-type data services. An additional interference margin for voice services is provided by suppressing interference from stream-type data services according to voice access requests and a varying interference status. Performance of the two schemes is evaluated by developing Markovian models. Numerical results show that the voice capacity is highly sensitive to the service holding time of data services while the performance measures of data services are not highly sensitive. Scheme H is a significant improvement over Scheme I for accommodating voice and stream-type data services

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7B
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• pp.679-689
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• 2006

Delivering multicast stream is one of the cost-saving approach in the large scale VOD environment. Because implementing VCR-like interactions for user's convenience in the multicast streaming system involves complex problems, we need the proper solutions for them. In this paper, we propose a hybrid scheme which uses the general P2P and the patching scheme with the Collaborative Interaction Streaming Scheme(CISS). CISS provides jumping functionability to the appropriate multicast session after VCR-like interaction in the environment in which multiple peers transmit VCR-like interaction streams to the VCR-like functionability request node to reduce the loads generated by frequent join or departure of peers at the multicast tree during providing VCR-like functionability. Therefore, with the proposed scheme we can distribute network traffic and reduce control overhead and latency. And to evaluate the performance of proposed scheme we compare it in the aspect of the performance of streaming delivery topology, control overhead and streaming quality with P2Cast[10] and DSL[11]. The simulation result shows that proposed P2Patching reduces about 30% of process overhead and enhances about $25{\sim}30%$ of streaming quality compared with DSL.