• Information Systems Review
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• v.12 no.3
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• pp.1-17
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• 2010

IT Systems based on Global Single Instance (GSI) can manage a corporation's internal information, resources and assets effectively and raise business efficiency through consolidation of their business process and productivity. But, It has also dangerous factor that IT system fault failure can cause a state of paralysis of a business itself, followed by huge loss of money. Many of studies have been conducted about fault-tolerance based on using redundant component. The concept of fault tolerance is rather simple but, designing and adopting fault-tolerance system is not easy due to uncertainty of a type and frequency of faults. So, Operational fault management that working after developed IT system is important more and more along with technical fault management. This study proposes the fault management process that including a pre-estimation method using TRM (Technical Reference Model) check point and event rule engine. And also proposes a effect of fault-free process through built fault management system to representative company of Hi-tech industry. After adopting fault-free process, a number of failure decreased by 46%, a failure time decreased by 56% and the Opportunity loss costs decreased by 77%.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.11
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• pp.589-598
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• 2007

In the group communication which has multiple data streams and various access privileges, it is necessary to provide group access control. The group members having the same access privilege are classified into one class, and the classes form a hierarchy based on the access relations. Then each class is assigned to a secret key. In the previous schemes, a single logical key graph is constructed from the hierarchy and each member always holds all secret keys of the classes he can access in the proactive manner. Thus, higher-privileged members hold more keys then lower-privileged members. However, if the hierarchy is large, each member manages too many keys and the size of multicast message in rekeying increases in proportion to the size of the hierarchy. Moreover, most of the members access a small portion of multiple data streams simultaneously. Therefore, it is redundant to receive rekeying message and update the keys in which he is not currently interested. In this paper, we present a new key management scheme that takes a reactive approach in which each member obtains the key of a data stream only when he wants to access the stream. Each member holds and updates only the key of the class he belongs. If he wants to get the key of other class, he derives it from his key and the public parameter. Proposed scheme considerable reduces the costs for rekeying, especially in the group where access relations are very complex and the hierarchy is large. Moreover, the scheme has another advantage that it easily reflects the change of access relations.

• Korean Journal of Cognitive Science
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• v.22 no.4
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• pp.469-494
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• 2011

It is well known that visual objects belonging to the same perceptual category compete for category-specific, limited-capacity attentional resource. However, it remains to be seen how perceptually identical objects interact with each other during visual analyses. Perceptually identical objects might suppress each other as much as categorically identical objects do. Alternatively, they might cooperate to generate a perceptual representation which is long lasting and robust to noise. Such possibilities were tested in the current research with three behavioral experiments using the Stroop task. As results, relative to a single distractor, Stroop interference was diluted by two different distractors of a category while it was enhanced by two perceptually identical distractors (Experiment 1). This redundancy effect disappeared when two different distractors associated with the same response were presented (Experiment 2), and it was not affected by the between- vs. within-hemisphere distractor presentations (Experiment 3). These findings indicate that the redundancy effect of distractors may be mediated by perceptual representations based on hemisphere-independent attentional resources. Overall, the current study supports the hypothesis that Stroop interference is constrained by category-specific attentional resources and further suggests that redundant presentations of a stimulus overcome such attentional constraints by facilitating perceptual processing.

• Korean Journal of Cognitive Science
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• v.24 no.3
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• pp.237-270
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• 2013

Determinism and compatibilism have thought that libertarianism contradicts the scientific view. This paper demonstrates that the hypothesis that free will exists does not cause any problems and contradictions, while maintaining pro-scientific view. Rather, determinism lacks scientific and demonstrative bases. At first, I reject dualistic self by assuming identity theory of the self and physical body & brain. Free will is a functional concept or property that can have multiple realization. Therefore we can recognize whether aliens or robots have free will through observation on their acts. 'Free will' is a functional kinds term like 'digestion'. As we know we have digestive function, we can know that we have free will even before knowing the necessity of its existence by understanding micro structure of human free will. The judgement that an individual has free will function depends on whether it has particular actions. Those actions are controlling and restraining actions in context, predicting future, making elaborate conditional sentences, etc. Real being of free will is the physical occupant of the function that makes those actions. Determinism is based on various kinds of misconceptions and misunderstandings. Determinists often confuse necessity of physical law and determinism. Another decisive misunderstanding is that free will postulates same conditions and different results from the same point of time. However, free will postulates that the two points of time are different. Because determinism is unnecessary redundant hypothesis influenced by religions, according to Ockham's Razor, determinism should be eliminated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.8
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• pp.1623-1636
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• 2009

A currently domestic governmental R&D business is early to 100. And this is each managed individually in 15 professional organizations of research and management by characteristics of a business. For this Reason, A redundant investment issue regarding national R&D occurs, and an issue regarding efficiency of R&D investment by insufficiency of systematic R&D research project and result management is continuously raised. Ministry of Education Science and Technology establishing National Science & Technology Information Service(NTIS) in order to solve these issues. NTIS is the national R&D Portal System which can support efficiency of research and development to result utilization in planning of national research and development. As data of the same meaning are named particularly in each organizations, and that made to different data types, It is an issue to be difficult to achieve high level qualify, accuracy of integrated data in case of integration of distributed data like NTIS In this paper We consider integrated DB constructions and Information Linking of R&D Participants/Projects/Results information in a NTIS system for data qualify Improvement, and then We analyze the cause of the data quality problem, and we propose the improvement plan for data quality elevation of NTIS system.

• The KIPS Transactions:PartD
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• v.10D no.4
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• pp.591-602
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• 2003

Delay and discontinuance phenomenon of service are cause by sudden increase of the network communication amount and the quantity consumed of resources when Internet users are driven excessively to a conventional single large database sewer. To solve these problems, spatial database cluster consisted of several single nodes on high-speed network to offer high-performance is risen. But, research about spatial join operation that can reduce the performance of whole system in case process at single node is not achieved. So, in this paper, we propose efficient parallel spatial join processing method in a spatial database cluster system that uses data partitions and replications method that considers the characteristics of space data. Since proposed method does not need the creation step and the assignment step of tasks, and does not occur additional message transmission between cluster nodes that appear in existent parallel spatial join method, it shows performance improvement of 23% than the conventional parallel R-tree spatial join for a shared-nothing architecture about expensive spatial join queries. Also, It can minimize the response time to user because it removes redundant refinement operation at each cluster node.

• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.389-405
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• 2001

In these days, we have increasing demands on the real-time services, especially for the multimedia data transmission in both of wired and wireless environments and thus efficient and stable ways of transmitting realtime data are needs. Although RTP is widely used for internet-based realtime applications, it cannot avoid packet losses, due to the use of UDP stack and its underlying layers. In the case of mobile computing applications, the packet losses are more frequent and consecutive because of the limited bandwidth. In this paper, we first statistically analyze the characteristics of packet losses in the wired and wireless communications, based on Gilbert model, and a new packet recovery scheme for realtime data transmission is presented. To reflect the transmission characteristics of the present network environment, our scheme makes the sender to dynamically adjust the amount of redundant information, using the current packet loss characteristic parameters reported by the receiver. Additionally, we use relatively large and discontinuous offset values, which enables us to recover from both of the random and consecutive packet losses. Due to these characteristics, our scheme is suitable for the mobile computing environment where packet loss rates are relatively high and varies rapidly in a wide range. Since our scheme is based on the analytic model form statistics, it can also be used for other network environments. We have implemented the scheme with Mobile IP and RTP/RTCP protocols to experimentally verify its efficiency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.93-99
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• 2008

In this paper, we propose new modulation schemes using the conventional CACB modulation with constant amplitude property. Also the proposed modulation schemes supports high transmission data rate by increasing the spectral efficiency. In order to obtain the high spectral efficiency, the $Q^2$PSK and CA-$Q^2$PSK are used. We explain the simplest combining modulation scheme of CACB and $Q^2$PSK (i.e., CACB-$Q^2$PSK). However, this modulation scheme cannot support the constant amplitude property. Hence the first CACB-CA-$Q^2$PSK (or CACB-CA-$Q^2$PSK I) modulation scheme is proposed for the constant amplitude property. In the modulation scheme, the redundant constant amplitude encoding (spectral efficiency decrease) is required. Therefore, the second CACB-CA-$Q^2$PSK (or CACB-CA-$Q^2$PSK II) modulation scheme is proposed retaining the constant amplitude and the spectral efficiency. Computer simulations show that the proposed CACB-CA-$Q^2$PSK II is the efficient modulation scheme.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.1
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• pp.18-29
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• 2008

NAND Flash memory has been growing popular storage device for the last years because of its low power consumption, fast access speed, shock resistance and light weight properties. However, it has the distinct characteristics such as erase-before-write architecture, asymmetric read/write/erase speed, and the limitation on the number of erasure per block. Due to these limitations, various Flash Translation Layers (FTLs) have been proposed to effectively use NAND flash memory. The systems that adopted the conventional FTL may result in severe performance degradation by the hot data which are frequently requested data for overwrite in the same logical address. In this paper, we propose a novel FTL algorithm called Adaptive Flash Translation Layer (AFTL) which uses sector mapping method for hot data and log-based block mapping method for cold data. Our system removes the redundant write operations and the erase operations by the separating hot data from cold data. Moreover, the read performance is enhanced according to sector translation that tends to use a few read operations. A series of experiments was organized to inspect the performance of the proposed method, and they show very impressive results.

• Archives of Plastic Surgery
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• v.36 no.3
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• pp.356-360
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• 2009

Purpose: Lipofibromatous Hamartoma(LFH) of nerve is a tumor - like lipomatous process principally involving the young persons. This is rare disease characterized by a soft slowly growing mass surrounding and infiltrating major nerves and their branches of the palm and digits. LFH of nerve usually affects the median nerve, with the most common sites of presentation being the distal forearm and hand in the wrist or palm. It may cause symptoms of compression neuropathy and is associated with macrodactyly. Recently, MRI plays a major role in confirming the diagnosis of LFH. Therefore, we present two cases of LFH in the hand with MRI features and surgical management. Methods: One is 6 - years - old female who presented with macrodactyly involving both the soft tissue and bony parts of the second, third and forth digits of her right hand. The other one is 16 - years - old man who presented involving the soft tissue of the second and third digits of his right hand, with pain and numbness, along with motor and sensory deficits in the median nerve distribution. To evaluation about LFH, we enforced preoperative MRI and physical examination. After confirming the diagnosis of LFH, we proposed decompression of all compromised peripheral nerve to help alleviate pain and paresthesia to reduce the likelihood of permanent motor and sensory sequelae. Results: A characteristic feature on MRI is the appearance of serpentiform nerve fascicle surrounded by fibro - fatty tissue within the expended nerve sheet. Distribution of fat between fascicles is asymmetric. Two cases were treated by limited debulking of the redundant tumor tissue and excision of epineurial fatty tissue. These cases were performed with relief of symptom. Conclusion: MRI not only confirms the diagnosis, it also provides a detailed assessment of nerve involvement preoperatively. Especially, on coronal images, the nerve has a spagetti - like appearance that is pathognomonic of LFH. Recommendations for early treatment include decompression of the carpal tunnel, debulking of the fibro - fatty sheath, microsurgical dissection of the neural elements and excision of involve nerve with or without grafting.