• The Journal of Society for e-Business Studies
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• v.14 no.4
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• pp.19-33
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• 2009

With the continuously increasing volume of e-commerce transactions, it is now popular to buy some products and to evaluate them on the World Wide Web. The product reviews are very useful to customers because they can make better decisions based on the indirect experiences obtainable through the reviews. Product Reviews are results expressing customer's sentiments and thus are divided into positive reviews and negative ones. However, as the number of reviews in on-line shopping increases, it is inefficient or sometimes impossible for users to read all the relevant review documents. In this paper, we present a sentiment analysis algorithm for automatically classifying subjective opinions of customer's reviews using opinion mining technology. The proposed algorithm is to focus on product reviews of on-line shopping, and provides summarized results from large product review data by determining whether they are positive or negative. Additionally, this paper introduces an automatic review analysis system implemented based on the proposed algorithm, and also present the experiment results for verifying the efficiency of the algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.39-54
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• 2012

Picture Archiving and Communication System (PACS) has been planted as one of the key infrastructures with an overall improvement in standards of medical informationization and the stream of digital hospitalization in recent days. The kind and data of digital medical imagery are also increasing rapidly in volume. This trend emphasizes the medical image compression for storing large-scale medical image data. Digital Imaging and Communications in Medicine (DICOM), de facto standard in digital medical imagery, specifies Run Length Encode (RLE), which is the typical lossless data compressing technique, for the medical image compression. However, the RLE is not appropriate approach for medical image data with bilateral symmetry of the human organism. we suggest two preprocessing algorithms that detect interested area, the minimum bounding rectangle, in a medical image to enhance data compression efficiency and that re-code image pixel values to reduce data size according to the symmetry characteristics in the interested area, and also presents an improved image compression technique for brain CT imagery with high bilateral symmetry. As the result of experiment, the suggested approach shows higher data compression ratio than the RLE compression in the DICOM standard without detecting interested area in images.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.10
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• pp.1173-1182
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• 1988

The stability, energetic efficiency and walking volume are affected by the geometric structure of legs of a walking robot. A quadruped walking robot is considered to have large stability margin among the walking robots and pantograph leg permits large walk stroke and mutually independent vertical and horizontal movements, but the kinematic characteristics are difficult to analyze. Graphical method may be useful to characterize three dimensional legged motion of the pantograph mechanism. We present the modelling method for three different quadruped robots with pantograph legs that have different joints mechanism. The modeled robots are animated by a path that is planned with respect to the center of body. In particular, graphical animation incorporates leg control to rotation and side walking and uses the window of Sun-3 system for displaying joint information.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.8
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• pp.47-54
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• 1998

With the increasing popularity of the use of large-volume image database in various application, it becomes imperative to build an efficient and fast retrieval system to browse through the entire database. We present a new method for a content-based image retrieval by using a variable block size and block matching algorithm. Proposed approach is reflecting image features that exploit visual cues such as color and space allocation of image and is getting the fast retrieval time by automatical convergence of retrieval times which adapt to wanting similarity value. We have implemented this technique and tested it for a database of approximately 150 images. The test shows that a 1.9 times fast retrieval time compare to J & V algorithm at the image retrieval efficiency 0.65 and that a 1.83 times fast retrieval time compare to predefined fixed block size.

• Journal of the Korea Society of Computer and Information
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• v.16 no.4
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• pp.149-157
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• 2011

Passive tags are inferior to active tags in processing efficiency, so they have difficulty in largevolume processing. The proposed protocol reduces the volume of computation in passive tags and, at the same time, improves authentication for enhanced safety and security. That is, different from existing RFID protocols that return the same value even if an error happens when the reader reads a tag, the improved RFID security protocol returns a new value using a re-counter and processes the computation part of a tag in the reader or in a back.end system. Even if the information of a tag is acquired by an malicious way, it is not actual information but encrypted information that is not usable. In addition, even if tag information is read in sequence, it is changed in each read, so the protocol is safe from Location Tracking.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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• pp.103-112
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• 2016

As supply chains are globalized, multinational companies are trying to optimize distribution networks using a hub and spoke structure. In this hub and spoke network structure, multinational companies locate regional distribution centers at hub airports, which serve demands in their corresponding regions. Especially when customers put higher priority on the service lead-time, hinterlands of international hub airports become ideal candidate locations for the regional hub distribution centers. By utilizing excellent airport and logistics services from hub airports, regional distribution centers in the hub airports can match supply with demand efficiently. In addition, regional hub distribution centers may increase air cargo volume of each airport, which is helpful in the current extremely competitive airport industry. In this paper, we classified locational preferences into three primary categories including demand, service and risk and applied the analytic hierarchy process methodology to prioritize factors of locational preferences. Primary preference factors include secondary factors. Demand factor contains access to current and prospect markets. Service factor comprises airport and logistics perspectives. Service factor in terms of airport operations includes secondary factors such as airport service and connectivity. Service factor in terms of logistics operations contains infrastructure and logistics operations efficiency. Risk factor consists of country and business risks. We also evaluated competitiveness of Asian hub airports in terms of candidate location for regional hub distribution centers. The candidate hub airports include Singapore, Hong Kong, Shanghai, Narita and Incheon. Based on the analytic hierarchy process analysis, we derived strategic implications for hub airports to attract multinational companies' regional hub distribution centers.

• Korean Journal of Optics and Photonics
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• v.5 no.3
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• pp.386-393
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• 1994

We have investigated output characteristics of XeCI excimer laser excited by transeverse electronbeam. We used e-beam output of 880 kV, 21 kA (70 ns, FWHM) and controlled current density of e-beam by pulsed magnetic coil (4.7 kG) which was fabricated around an e-beam diode (A-K gap is 21 mm) and laser chamber. We have obtained 35 J (4 atm) of e-beam deposition energy injected into laser media. The deposition energy was converted from an exposure area of Radcolor film and rising pressure of gas media which is measured by pressure jump method. The excited volume of $320cm^{3}$ was calculated. The maximum efficiency of 1.7% was obtained with the mixing ratio of HCllXe/Ar==0.2/ 6.3/93.5% and total pressure of 3 atm. Also laser output energy and specific energy were obtained 0.52 J and 1.7 J/I, respectively. For the analysis of experimental results we have developed computer simulation code. From the good agreements with the results of experiment and simulation we could theoretically explain the XeCI* formation channel. relaxation channel, and absorption channel of 308 nm.308 nm.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.3
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• pp.307-314
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• 2014

PURPOSE: The purpose of this study was to investigate the effects of high intensity intermittent training on cardiopulmonary capacity in canoe and kayak paddlers. METHODS: A total of 16 canoe and kayak paddlers were participated in this study. Experimental group(n=8) was performed high-intensity intermittent training and control group(n=8) was moderate intensity training. All subjects performed a treadmill test in order to compare the difference before and after the intervention. Finishing the test, all subjects were measured to their heart rate(HR), forced vital capacity(FVC), forced expiratory volume in one second (FEV1) and forced expiratory ratio(FEV1/FVC). Recovery of heart rate(RHR) was calculated using the HR. HR and pulmonary flow values was measured before and during the intervention period per 2, 4, 6 and 8 weeks. To compare the differences over time between experimental group and the control group, used(time${\times}$group) two-way repeated measures ANOVA. One-way repeated ANOVA was performed to determine where differences over time within-group. RESULTS: One-way repeated ANOVA revealed a significant difference in the experimental and control group. In experimental group, %RHR3min and FEV1 were significantly increased after 4 weeks(p<.05). Also, %RHR1min, FVC and FEV1/FVC were significantly increased after 6 weeks(p<.05). In control group, %RHR1min, %RHR3min, FVC, FEV1 and FEV1/FVC were significantly increased after 6 weeks(p<.05). CONCLUSION: Not only moderate training but also high-intensity intermittent training contributes to cardiopulmonary capacity in canoe and kayak paddlers. Although high-intensity intermittent training is very short time, the training has high degree of efficiency. Therefore, developed this training in the future, it will be better to improve the cardiopulmonary capacity for athletes and healthy people.

• Tribology and Lubricants
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• v.26 no.2
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• pp.136-141
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• 2010

In an oil hydraulic vane pump for an automobile, it is very important that the vane doesn't separate from the camring inner race during the operation of the vane pump. The vane generally has not only the oil hydraulic force acting on the bottom face to contact to camring inner race but there is also an inertial force and viscous force. Because the oil hydraulic force is much larger than the other forces, the contact state between the vane tip and the camring inner race is sufficient. However, the contact state between the vane tip and the camring inner race is only affected by the inertial and viscous forces during the delivery of the vane pump, because the oil hydraulic force acting on the vane is in equilibrium. If the inertial force is larger than the viscous force, which happens when the vane is separated from the camring inner race, the delivery of the vane pump can become unstable or the volume efficiency can become decrease rapidly. Therefore, in this paper, the state of the contact between the vane and the camring is considered. The results show that the rotating speed of the shaft, the operating temperature of the oil, the clearance between the vane and the rotor, and the mass of the vane exert a great influence on the state of the contact between the vane and the camring.

• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.53-60
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• 1997

A series of batch and lab-scale pilot tests were conducted to optimize the design parameters for the application of soil washing techniques to the soil contaminated by heavy metals. Cu, Pb, and Zn were selected as target heavy metals. The concentrations of Cu, Pb, and Zn were 500mg/kg dry soil, 1, 000mg/kg dry soil, and 500mg/kg dry soil, respectively. Citric acid and oxalic acid were used for the extractants. In the batch tests, the extraction efficiencies for Cu, Pb, and Zn were 79%, 72%, 72%, respectively. The proper extractant concentration and dilution ratio(weight/volume) for Cu and Pb were turned to be citric acid 50mM and 1:5, respectively. The extraction efficiencies were enhanced with the addition of 1~2% OA-5 or SDS. From pilot scale tests for Pb, first stage and second stage of soil washing resulted in the extraction efficiency of 59% and 78%, respectively.