• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1C
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• pp.69-77
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• 2002

Sine digital signal processing for motion pictures requires huge amount of data computation to store, manipulate and transmit, more effective data compression is necessary. Therefore, the ITU-T recommended H.26x as data compression standards for digital motion pictures. The data compression method that eliminates time redundancies by motion estimation using relationship between picture frames has been widely used. Most video conding systems employ block matching algorithm for the motion estimation and compensation, and the algorithm is based on the minimun value of cast functions. Therefore, fast search algorithm rather than full search algorithm is more effective in real time low data rates encodings such as H.26x. In this paper, motion estimation employing the Nearest-Neighbors algorithm is designed to reduce search time using FPGA, coded in VHDL, and simulated and verified using Xilink Foundation.

• Journal of KIISE:Databases
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• v.34 no.2
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• pp.141-152
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• 2007

Selectivity estimation has been a crucial component in query optimization in relational databases. While extensive researches have been done on this topic for the predicates of numerical data, only little work has been done for substring predicates. We propose novel suffix tree transform algorithms for this problem. Unlike previous approaches where a full suffix tree is pruned and then an estimation algorithm is employed, we transform a suffix tree into a suffix graph systematically. In our approach, nodes with similar counts are merged while structural information in the original suffix tree is preserved in a controlled manner. We present both an error-bound algorithm and a space-bound algorithm. Experimental results with real life data sets show that our algorithms have lower average relative error than that of the previous works as well as good error distribution characteristics.

• Journal of Information Processing Systems
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• v.11 no.1
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• pp.57-75
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• 2015

In evaluating the performance of a dual-hop wireless link, the effects of large and small scale fading has to be considered. To overcome this fading effect, several schemes, such as multiple-input multiple-output (MIMO) with orthogonal space time block codes (OSTBC), different combining schemes at the relay and receiving end, and orthogonal frequency division multiplexing (OFDM) are used in both the transmitting and the relay links. In this paper, we first make compare the performance of a two-hop wireless link under a different combination of space diversity in the first and second hop of the amplify-and-forward (AF) case. Our second task in this paper is to incorporate the weak signal of a direct link and then by applying the channel model of two random variables (one for a direct link and another for a relayed link) we get very impressive result at a low signal-to-noise ratio (SNR) that is comparable with other models at a higher SNR. Our third task is to bring other three schemes under a two-hop wireless link: use of transmit antenna selection (TAS) on both link with weak direct link, distributed Alamouti scheme in two-hop link and single relay antenna with OFDM subcarrier. Finally, all of the schemes mentioned above are compared to select the best possible model. The main finding of the paper is as follows: the use of MIMO on both hops but application TAS on both links with weak direct link and the full rate OFDM with the sub-carrier for an individual link provide a better result as compared to other models.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3C
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• pp.288-296
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• 2009

In POCS (projection onto convex sets)-based reconstruction of HR (high resolution) image, the quality of reconstructed image is gradually improved through iterative motion estimation and image restoration. The amount of computation, however, increases because of the repeated inter-frame motion estimation. In this paper, an HR reconstruction algorithm is proposed where modified ARPS (adaptive rood pattern search) and POCS are simultaneously performed. In the modified ARPS, the motion estimates obtained from phase correlation or from the previous steps in POCS restoration are utilized as the initial reference in the motion estimation. Moreover, estimated motion is regularized with reference to the neighboring blocks' motion to enhance the reliability. Computer simulation results show that, when compared to conventional methods which are composed of full search block matching and POCS restoration, the proposed method is about 30 times faster and yet produces HR images of almost equal or better quality.

• Journal of the Society of Disaster Information
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• v.2 no.1
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• pp.139-155
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• 2006

Over the past two decades suicide terrorism has become an ever-widening phenomenon. When suicide terrorism was first introduced in the Middle East it seemed that this new phenomenon was invincible and that it might change the innate imbalance between terror groups and their rivalry governments. This did not in fact occur. Looking at history of terrorism, it can be seen that suicide attacks are in actuality a very old modus operandi. However, contemporary suicide terrorism differs from such historical tactics, just as the whole phenomenon of terrorism differs from ancient modes of warfare. Modern suicide terrorism is aimed at causing devastating physical damage. through which it inflicts profound fear and anxiety. Its goal is to produce a negative psychological effect on an entire population rather than just the victims of the actual attack. The relatively high number of casualties guaranteed in such attacks, which are usually carried out in crowded areas, ensures full media coverage. Thus, suicide terrorism, ranks with other spectacular modus operandi such as blowing up airplanes in mid air or the use of Weapons of Mass Destruction as a sure means to win maximum effect. For the purposes of this paper a suicide terror attack is defined as a politically motivated violent attack perpetrated by a self-aware individual (or individuals) who actively and purposely causes his own death through blowing himself up along with his chosen target. The perpetrator's ensured death is a precondition for the success of his mission. The greatest potential risk suicide terrorism may pose in future is if terrorists carry out operations combined with other spectacular tactics such as blowing up airplanes or the use of Weapons of Mass Destruction. Such a combination will increase immensely the death toll of a single terror attack and will have a shocking psychological effect on public moral. At this level suicide terrorism would constitute a genuine strategic threat and would probably be confronted as such. This study portrays a general overview of the modern history of suicide terror activity worldwide, focusing on its main characteristics and the various aims and motivations of the terror groups involved. In addition, This study provides an overview what is to be done to prevent such terrorist attacks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4A
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• pp.364-370
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• 2002

In this paper, we propose a VLSI array architecture for high speed processing of FBMA. First of all, the sequential FBMA is transformed into a single assignment code by using the index space expansion, and then the dependance graph is obtained from it. The two dimensional VLSI array is derived by projecting the dependance graph along the optimal direction. Since the candidate blocks in the search range are overlapped with columns as well as rows, the processing elements of the VLSI array are designed to reuse the overlapped data. As the results, the number of data inputs is reduced so that the processing performance is improved. The proposed VLSI array has (N$^2$+1)${\times}$(2p+1) processing elements and (N+2p) input ports where N is the block size and p is the maximum search range. The computation time of the rat reference block is (N$^2$+2(p+1)N+6p), and the block pipeline period is (3N+4p-1).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.1
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• pp.159-169
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• 1994

A multichannel optical slotted ring network is designed using a wavelength division multiplexing(WDM) technique and photonic packet switching devices. The electronics speed bottleneck is removed out of the ring, which allows utilization of the full bandwidth for the optical fiber transmission medium. The ring channel adopts a slotted ring concept with a destination cell remove strategy for the eing access mechanism. The slot size in the ring is selected as the same as that of ATM based cell in order to be used as B-ISDN Access Networks. In this paper, we devised a mathematical method to measure the average transfer delay characteristics of the network. The analytical method turned out to yield accurate results over a broad range of parameters in comparison to simulation results. From the study, we observed the average transfer delay of the network as the network parameters vary.

• Journal of Internet Computing and Services
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• v.10 no.4
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• pp.25-33
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• 2009

In the paper, we proposed a new system to retrieve 3D wrinkle data based on stereo images. Usually, 3D reconstruction based on stereo images or video is very popular and it is the research focus, which has been applied for culture heritage, building and other scene. The target is object measurement, the scene depth calculation and 3D data obtained. There are several challenges in our research. First, it is hard to take the full information wrinkle images by cameras because of light influence, skin with non-rigid object and camera performance. We design a particular computer vision system to take winkle images with a long length camera lens. Second, it is difficult to get the dense stereo data because of the hard skin texture image segmentation and corner detection. We focus on semi-dense stereo matching algorithm for the wrinkle depth. Compared with the 3D scanner, our system is much cheaper and compared with the physical modeling based method, our system is more flexible with high performance.

• Korean Journal of Ecology and Environment
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• v.44 no.4
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• pp.364-372
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• 2011

The pale chub (Zacco platypus) is generally found in Asian countries, such as Korea, Japan, and China. Nevertheless, very little information exists about the genes involved in the metabolism of xenobiotics in this species. This species is useful in monitoring the environmental impact on various pollutants in freshwater as a sentinel fish species. We cloned the full-length cDNA sequence of xenobiotic metabolizing cytochrome P450 1A (CYP1A) gene from Z. platypus and characterized it. Tissue distribution and timedependent induction of CYP1A were studied by real-time RT-PCR. Induction pattern of CYP1A was studied by exposing the fish to an arylhydrocarbon receptor agonist, ${\beta}$-naphthoflavone (BNF). The liver showed the highest level of expression in basal state as well as BNF- treated fish. However, appreciable levels of expression were also recorded in Gill and kidney and the least level of expression was observed in the eye. The results of the time-course study revealed an induction in the liver, brain, and gills after 6 h and 12 h in most of the tissues. This study provides an insight into the xenobiotics metabolizing system of Z. platypus and offers baseline information for further research related to biomarker, stress, and adaptive response of this ecologically important fish species in the freshwater environment.

• Journal of the Korean Society for Library and Information Science
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• v.10
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• pp.3-37
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• 1983

1. Library practice education in Korea is in the form of field experience, that is, Practicum, which is one type of field experience. 2. The practicum is a short-term work experience guided by the academic institutions. (2 to 6 weeks of full time employment in a library, or one to two semesters of approximately 10 to 12 hours weekly) 3. Field work is largely accepted as a required subject. 4. Field work is usually carried out during the first semester of senior year. (or of sophomore year in junior college) 5. Libraries in other universities (or in other institutions) can beused for a student's field work. But the current tendency is to use his or her own university's library. 6. Most universities give one credit for 2 weeks' field work. 7. The method of evaluation is strict: A or 'excellent' (above 90), B or 'good' (above 80), C or 'fair' (above 70), D or 'bad' (above 60). 8. The expense of field work is usually included in the tuition fees. However, some think that an additional fees should be collected in the case of special practice. 9. Respondents to my survey say that the field experience is necessary so that professional librarians can connect theory and practice. 10. They also indicate that there are some problems in library practice education: administrative difficulties in the department chairman's office, the burden on professors in the library being used, and the limited number of libraries in which the field work is practicable. 11. The Department of Library Science is responsible primarily for providing faculty supervision over the students, and secondarily for the preparation of evaluation cards and field work reports. 12. Most of the faculty respondents use evaluation cards for the field work, some of which serve as grade sheets, some as field work diaries, and some as field work reports.