• Journal of the Korean Society for information Management
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• 제19권1호
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• pp.23-46
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• 2002

With explosively increasing digital contents, library and Information center should have a new role between knowledge providers and knowledge users as information brokering organization. Electronic transaction system should be required for performing this brokering service since economic value is added to information and knowledge in information society. The developments and changes around library are keeping up with increasing building digital library and digitalizing printed sources. With the rapidly changing circumstances, the Internet is currently witnessing an explosive growth. By serving as a virtual information resource. the Internet can dramatically change the way business is conducted and Information is provided. However because of features o( the Internet like openness and information sharing, it has fundamental vulnerabilities in security issues. For Instance, disclosure of private information and line eavesdropping such as password, banking account, transaction data on network and so on are primary obstruction factors to activation of digital contents delivery on network. For high network security and authentication, this paper looks at smart card technologies and proposes multi-authentication protocol based on smart card on open network, implements and analyzes it.

• Journal of KIISE:Information Networking
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• 제29권5호
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• pp.583-594
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• 2002

Assuring the security of group communications such as tole-conference and software distribution requires a common group key be shared among the legal members in a secure manner. Especially for large groups with frequent membership change, efficient rekey mechanism is essential for scalability. One of the most popular ways to provide sealable rekey is to partition the group into several subgroups. In this paper, we propose a two-layered key management scheme which combines DEP and CBT, a protocol in which subgroup manager cannot access the multicast data and another that has a multi-core, respectively. We also select sub-group key management protocols suitable for our structure and design new rekey protocols to exclude the subgroup managers from the multicast data. Compared to previous protocols based on CBT, our scheme provides forward secrecy, backward secrecy and scalability. This would reduce the number of encryption and decryption for a rekey message and would improve the efficiency number of rekey messages and the amount of information related to group members that group managers must maintain compared to DEP.

• Journal of Gastric Cancer
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• 제5권2호
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• pp.79-88
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• 2005

Quality assurance may be defined as the complete set of systemic actions that is required to achieve a better treatment result by standardizing treatment and by using various audit programs. In general, application of a quality assurance program in surgery is considered to be more difficult than it is in chemotherapy or radiotherapy. However, recently, the importance of quality assurance in the surgical field has been emphasized in clinical trials comparing different surgical procedures and evaluating the role of postoperative adjuvant therapy. In the case of gastric cancer surgery, excellent quality assurance programs have rarely been applied in most large prospective clinical trials. Although the quality assurance in Dutch trial was conducted very systemically and strictly, the situation is quite different from ours. On the other hand, several quality assurance programs in Japanese trials comparing D2 and D2 plus para-arotic lymph node dissection seem to be applicable to Korean clinical trials. Several factors, including selection of appropriate surgeons based on personal experience and annual number of operations, standardization of surgical procedures by education and consensus, development of a unified database program, application of standardized perioperative management, and standardization of pathologic examination, are required to guarantee a successful multi-institutional prospective clinical trial. In contrast, one needs to realize that protocols that are too strict and sophisticated can make the enrollment of patients and surgeons more difficult and can promote protocol violation during the clinical trials. (J Korean Gastric Cancer Assoc 2005;5:79-88)

• Journal of Biomedical Engineering Research
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• 제36권6호
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• pp.276-282
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• 2015

Recently, during the multi-level fusion with pedicle screws, interspinous spacer are sometimes substituted for the most superior level of the fusion in an attempt to reduce the number of fusion level and likelihood of degeneration process at the adjacent level. In this study, a finite element (FE) study was performed to assess biomechanical efficacies of the interspinous spacer combined with posterior lumbar fusion with a previously-validated 3-dimensional FE model of the intact lumbar spine (L1-S1). The post-operative models were made by modifying the intact model to simulate the implantation of interspinous spacer and pedicle screws at the L3-4 and L4-5. Four different configurations of the post-op model were considered: (1) a normal spinal model; (2) Type 1, one-level fusion using posterior pedicle screws at the L4-5; (3) Type 2, two-level (L3-5) fusion; (4) Type 3, Type 1 plus Coflex$^{TM}$ at the L3-4. hybrid protocol (intact: 10 Nm) with a compressive follower load of 400N were used to flex, extend, axially rotate and laterally bend the FE model. As compared to the intact model, Type 2 showed the greatest increase in Range of motion (ROM) at the adjacent level (L2-3), followed Type 3, and Type 1 depending on the loading type. At L3-4, ROM of Type 2 was reduced by 34~56% regardless of loading mode, as compared to decrease of 55% in Type 3 only in extension. In case of normal bone strength model (Type 3_Normal), PVMS at the process and the pedicle remained less than 20% of their yield strengths regardless of loading, except in extension (about 35%). However, for the osteoporotic model (Type 3_Osteoporotic), it reached up to 56% in extension indicating increased susceptibility to fracture. This study suggested that substitution of the superior level fusion with the interspinous spacer in multi-level fusion may be able to offer similar biomechanical outcome and stability while reducing likelihood of adjacent level degeneration.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제13권5호
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• pp.17-26
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• 2013

ISO/IEC 29157 originally developed in the Republic of Korea and is based on commercially available PicoCast v1.0. ISO/IEC JTC1 SC6 was registered by the international standard on May 2010. A single platform for a variety of applications and media formats to support development objectives were. ISO/IEC 29157 based wireless networks, ie, Pico-net to master node periodically transmit sync signal is synchronized to the number of slave nodes have the communications structure. Pico-net also supports a variety of network topologies and direct communication between nodes(single-hop communication) and QoS is guaranteed. But Pico-net network structure has the following problems. Loss of communication problems due to mobile nodes, resulting in limitations of node mobility and wireless network operation range of conventional wireless networks operating range less than 1/4 was reduced to the problem. In this paper, a possible solution to the problems mentioned is proposed, using multi-hop communication technology and sync signal transmission technology between nodes.

• Tuberculosis and Respiratory Diseases
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• 제68권2호
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• pp.80-86
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• 2010

Background: Recently, many institutions have acquired multi-detector computed tomography (MDCT) systems. This made it easier and more convenient to use MDCT as a initial diagnostic modality for hemoptysis. The purpose of this study was to evaluate the usefulness of MDCT before bronchoscopy and/or bronchial arterial embolization (BAE) for hemoptysis. Methods: We studied a total of 125 patients with hemoptysis who underwent, between 2006 and 2008, MDCT in a routine protocol before bronchoscopy and/or BAE. One hundred two patients underwent bronchoscopy and 29 patients underwent BAE. We compared the usefulness of MDCT and bronchoscopy for detecting the bleeding site and identifying the cause. We also evaluated our ability, using MDCT, to detect instances where the bronchial artery caused hemoptysis. Results: The rate of detection of a bleeding site was 75.5% on MDCT and 50.9% on bronchoscopy. MDCT and bronchoscopy detected the bleeding site in agreement in 62.7% of patients. MDCT alone found the bleeding site in 27.5% of cases. MDCT identified the cause of hemoptysis in 77.5% and bronchoscopy in 11.8%. In 29 patients who underwent BAE, we detected a total of 37 hypertrophied bronchial arteries that were causing hemoptysis. Of 37 bronchial arteries, 23 (62.2%) were depicted on MDCT. Conclusion: MDCT is superior to bronchoscopy for detecting the bleeding site and identifying the cause of hemoptysis. MDCT can also predict the side of affected bronchial artery with depiction of hypertrophied bronchial artery and localizing the bleeding site. Doing MDCT before bronchoscopy and BAE can provide a guideline for the next step.

• Journal of Intelligence and Information Systems
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• 제10권3호
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• pp.73-89
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• 2004

Since people have come to access more and more information about products with the proliferation of the Internet, more and more customer-to-customer e-marketplaces are being introduced with rapidly increasing transaction volumes. As the role of customer-to-customer electronic commerce has become increasingly regarded as vital to the economy, much research has delved into developing intelligent agent systems to efficiently support customer-to-customer electronic commerce. Most of this research, however, has focused only on supporting simple negotiation for the price of common goods along the time span. To expand the negotiation object to the differentiated goods, the customer must be allowed to negotiate over multi-at-tributes of the product besides the price, including the attributes related to the transaction activity itself, such as delivery time and payment method. To satisfy this requirement, we propose an agent marketplace for differentiated goods where the agent of a customer can negotiate not only the price but also the various attributes of the product and the transaction in order to achieve a better utility level for both buyer and seller. The formal protocol and the architecture issues to support the proposed e-marketplace and agents are also addressed.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제22권6호
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• pp.1-10
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• 2021

The interest in underwater acoustic sensor networks (UWASNs), along with the rapid development of underwater industries, has increased. To operate UWASNs efficiently, it is important to adopt well-designed medium access control (MAC) protocols that prevent collisions and allow the sharing of resources between nodes efficiently. On the other hand, underwater channels suffer from a narrow bandwidth, long propagation delay, and low data rate, so existing terrestrial node pairing schemes for non orthogonal multiple access (NOMA) cannot be applied directly to underwater environments. Therefore, a multi-dimensional node pairing scheme is proposed to consider the unique underwater channel in UWASNs. Conventional NOMA schemes have considered the channel quality only in node pairing. Unlike previous schemes, the proposed scheme considers the channel gain and many other features, such as node fairness, traffic load, and the age of data packets to find the best node-pair. In addition, the sender employs a list of candidates for node-pairs rather than path loss to reduce the computational complexity. The simulation results showed that the proposed scheme outperforms the conventional scheme by considering the fairness factor with 23.8% increases in throughput, 28% decreases in latency, and 5.7% improvements in fairness at best.

• KIPS Transactions on Computer and Communication Systems
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• 제11권8호
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• pp.269-280
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• 2022

With the rise of a decentralized finance market (so called, DeFi) using blockchain technology, users and capital liquidity of decentralized finance applications are increasing significantly. The Automated Market Maker (AMM) is a protocol that automatically calculates the asset price based on the liquidity of the decentralized trading platform, and is currently most commonly used in the decentralized exchanges (DEX), since it can proceed the transactions by utilizing the liquidity pool of the trading platform even if the buyers and sellers do not exist at the same time. However, Automated Market Maker have some disadvantages since the cost efficiency of each transaction using Automated Market Maker depends on the liquidity size of some liquidity pools used for the transaction, so the smaller the size of the liquidity pool and the larger the transaction size, the smaller the cost efficiency of the trade. To solve this problem, some platforms are adopting Transaction Path Routing Algorithm that bypasses transaction path to other liquidity pools that have relatively large size to improve cost efficiency, but this algorithm can be further improved because it uses only a single transaction path to proceed each transaction. In addition to just bypassing transaction path, in this paper we proposed a Multi-Path Routing Algorithm that uses multiple transaction paths simultaneously by distributing transaction size, and showed that the cost efficiency of transactions can be further improved in the Automated Market Maker-based trading environment.

• Journal of the Korea Society of Computer and Information
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• 제14권11호
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• pp.105-111
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• 2009

The study aims to propose the intelligent clustering technique that calculates the distance by improving the problems of multi-hop clustering technique for inter-vehicular secure communications. After calculating the distance between vehicles with no connection for rapid transit and clustering it, the connection between nodes is created through a set distance vale. Header is selected by the distance value between nodes that become the identical members, and the information within a group is transmitted to the member nodes. After selecting the header, when the header is separated due to its mobility, the urgent situation may occur. At this time, the information transfer is prepared to select the new cluster header and transmit it through using the intelligent cluster provided from node by the execution of programs included in packet. The study proposes the cluster technique of the intelligent distance estimation for the mobile Ad-hoc network that calculates the cluster with the Store-Compute-Forward method that adds computing ability to the existing Store-and-Forward routing scheme. The cluster technique of intelligent distance estimation for the mobile Ad-hoc network suggested in the study is the active and intelligent multi-hop cluster routing protocol to make secure communications.