• Progress in Medical Physics
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• v.25 no.2
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• pp.65-71
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• 2014

A Varian Portal Dosimetry system was compared to an isocentrically mounted MapCHECK 2 diode array for volumetric modulated arc therapy (VMAT) QA. A Varian TrueBeam STx with an aS-1000 digital imaging panel was used to acquire VMAT QA images for 13 plans using four photon energies (6, 8, 10 and 15 MV). The EPID-based QA images were compared to the Portal Dose Image Prediction calculated in the Varian Eclipse treatment planning system (TPS). An isocentrically mounted Sun Nuclear MapCHECK 2 diode array with 5 cm water-equivalent buildup was also used for the VMAT QAs and the measurements were compared to a composite dose plane from the Eclipse TPS. A ${\gamma}$ test was implemented in the Sun Nuclear Patient software with 10% threshold and absolute comparison at 1%/1 mm (dose difference/distance-to-agreement), 2%/2 mm, and 3%/3 mm criteria for both QA methods. The two-tailed paired Student's t-test was employed to analyze the statistical significance at 95% confidence level. The average ${\gamma}$ passing rates were greater than 95% at 3%/3 mm using both methods for all four energies. The differences in the average passing rates between the two methods were within 1.7% and 1.6% of each other when analyzed at 2%/2 mm and 3%/3 mm, respectively. The EPID passing rates were somewhat better than the MapCHECK 2 when analyzed at 1%/1 mm; the difference was lower for 8 MV and 10 MV. However, the differences were not statistically significant for all criteria and energies (p-values >0.05). The EPID-based QA showed large off-axis over-response and dependence of ${\gamma}$ passing rate on energy, while the MapCHECK 2 was susceptible to the MLC tongue-and-groove effect. The two fluence-based QA techniques can be an alternative tool of VMAT QA to each other, if the limitations of each QA method (mechanical sag, detector response, and detector alignment) are carefully considered.

• Journal of Power Electronics
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• v.5 no.2
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• pp.151-159
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• 2005

The errors generated from current measurement paths are inevitable, and they can be divided into two categories: offset error and scaling error. The current data including these errors cause periodic speed ripples which are one and two times the stator electrical frequency respectively. Since these undesirable ripples bring about harmful influences to motor driving systems, a compensation algorithm must be introduced to the control algorithm of the motor drive. In this paper, a new compensation algorithm is proposed. The signal of the integrator output of the d-axis current regulator is chosen and processed to compensate for the current measurement errors. Usually the d-axis current command is zero or constant to acquire the maximum torque or unity power factor in the ac drive system, and the output of the d-axis current regulator is nearly zero or constant as well. If the stator currents include the offset and scaling errors, the respective motor speed produces a ripple related to one and two times the stator electrical frequency, and the signal of the integrator output of the d-axis current regulator also produces the ripple as the motor speed does. The compensation of the current measurement errors is easily implemented to smooth the signal of the integrator output of the d-axis current regulator by subtracting the DC offset value or rescaling the gain of the hall sensor. Therefore, the proposed algorithm has several features: the robustness in the variation of the mechanical parameters, the application of the steady and transient state, the ease of implementation, and less computation time. The MATLAB simulation and experimental results are shown in order to verify the validity of the proposed current compensating algorithm.

• Journal of the Korean housing association
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• v.20 no.1
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• pp.91-99
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• 2009

With the development of the internet and the spread of 'digital home', apartment houses equipped with the homepages connecting apartment houses as one cyberspace unit have increased. The virtual community with a homepage in apartment complex have improved the effect on management businesses in the side of a apartment manager and increased the importance of the space with a strong tie between residents in the side of residents. But the apartment residents didn't make full use of the virtual community because they have the low level of recognition of it. Therefore, this study attempted to present basic materials for the scheme to revitalize the virtual community. For this purpose, it attempted to find residents' recognition of and participation in the virtual community and demand for the classified contents conducted before this study. In the research method, it conducted the questionnaire research. The results are as follows. 1) First of all, It was found that the apartment residents had the low level of recognition of the virtual community. There was a significant difference according to the degree and the level of using the internet. Some easy-access programs are necessary. 2) The apartment residents took part in the virtual community about 67 percents because there was a lack of the public relation of the virtual community. 3) It was found that there was a significant positive correlation between the level of recognition and participation. 4) An attempt was made to identify the apartment residents' demand for the type of virtual community contents. It was found that most of contents were needed. 'apartment complex introduction and management information' showed the highest score among them. 5) Most respondents are affirmative to the virtual community. Therefore the residential community could be reinforced if the contents of virtual community is developed and well operated in the future.

• The Korean Journal of Pain
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• v.25 no.3
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• pp.151-154
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• 2012

Background: The aim of this study was to document the optimal spacing of two cannulae to form continuous strip lesions and maximal surface area by using water-cooled bipolar radiofrequency technology. Methods: Two water-cooled needle probes (15 cm length, 18-gauge probe with 6 mm electrode tip) were placed in a parallel position 10, 20, 24, 26, and 28 mm apart and submerged in egg white. Temperatures of the probes were raised from $35^{\circ}C$ to $90^{\circ}C$ and the progress of lesion formation was photographed every 1 minute with the increase of the tip temperature. Approximately 30 photographs were taken. The resultant surface areas of the lesions were measured with the digital image program. Results: Continuous strip lesions were formed when the cannulae were spaced 24 mm or less apart; monopolar lesions around each cannula resulted if they were spaced more than 26 mm apart. Maximal surface areas through the formation of continuous strip lesion were 221 $mm^2$, 375 $mm^2$, and 476 $mm^2$ in 10, 20, and 24 mm, respectively. Summations of maximal surface area of each monopolar lesions were 394 $mm^2$ and 103 $mm^2$ in 26 and 28 mm, respectively. Conclusions: Water-cooled bipolar Radiofrequency technology creates continuous "strip" lesions proportional in size to the distance between the probes till the distance between cannulae is 24 mm or less. Spacing the cannulae 24 mm apart and treating about $80^{\circ}C$ for 24 minutes maximizes the surface area of the lesion.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.1
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• pp.166-183
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• 2013

It requires a lot of costs and manpower to manage an election. The electronic voting scheme can make the election system economic and trustful. The widespread use of smart phones causes mobile voting to be a major issue. The smart phone can be used as a mobile voting platform since it can carry out many services in addition to basic telephone service. To make mobile voting practical and trustful, we analyzed two subjects of study. Firstly, the way to make a biometric based mobile ID, which has legal binding forces. In mobile voting, user identification is accomplished on line since the voter should be able to vote wherever they go. The digital ID conducts a similar role to the need for a resident card. The user's identity is bound to the resident card legally. To bind the user's identity to the smart phone, we use USIM. Biometric recognition is also needed to authenticate the user, since the user cannot prove him or her on line face-to-face. The proposed mobile ID can be reissued by means of introducing a random secret value. Secondly, the mobile voting scheme is proposed where candidates can accept election results without doubt. The goal of an election is to select a leader among two or more candidates. Existing electronic voting schemes mainly focus on the study of ballot verification accomplished by voters. These approaches are not safe against collusion attacks where candidates and the election administration center are able to collude to fabricate election results. Therefore, a new type of voting and counting method is needed where candidates can directly take part in voting and counting stages. The biometric based multi-signature scheme is used to make the undeniable multi-signed ballot. The ballot cannot be verified without the help of all candidates. If candidates accept election results without a doubt, the fairness of the election is satisfied.

• Journal of Acupuncture Research
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• v.31 no.2
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• pp.173-182
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• 2014

Objectives : There are few reports on treatment of thoracic outlet syndrome in the field of traditional Korean medicine. The aim of this study is to report a case of a 29-year-old male patient diagnosed with thoracic outlet syndrome, whose symptoms were relieved after 3-week integrated Korean medical treatment. Methods : A patient diagnosed with thoracic outlet syndrome was admitted into the Korean medicine hospital. The patient had left shoulder pain and left arm numbness. The pain was worse if it had become cold. The patient was treated using Sa-am acupuncture(Daejangseunggyeok), sweet bee venom acupuncture, herbal medicine and other treatment including physical therapy from September 7th to 27th of 2012. Improvement of the patient's symptoms was evaluated by verbal numerical rating scale(VNRS), skin surface temperature difference between the left and right symmetric part of digital infrared thermographic image(DITI). Results : After 3-weeks of treatment, VNRS decreased and skin surface temperature difference between the left and right symmetric part of DITI showed moderate improvement. Conclusions : The results suggest that integrated Korean medical treatment may affect to reduce the symptoms of thoracic outlet syndrome. Further study is needed to evaluate the importance of this report.

• Management & Information Systems Review
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• v.29 no.4
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• pp.89-108
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• 2010

Social Network Service(SNS) indicates the service to promote mutual friendship built in online focused on social relation between people. While a demand and concern of the service gets higher now more than ever, there are a lack of the approach in aspect of both technology and service still. 'Facebook' is the most famous in the world and the biggest in user number among various social network service. We investigate the key factors of 'Facebook' based on the side of approach both technology and service. We observe the behavior of users who have rich experience on using the social network service to find it. The result of this study reveals that an asynchronous method related to the technology drive to improve a sociality in social media. Furthermore, we find that openness connected with the technology force to intent the closed attribute in service through user observation. It is the unique qualities social media holds. The successful social network service can be expected if social media are developed to concern these factors.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.4
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• pp.117-125
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• 2014

Korea's first X-band SAR satellite KOMPSAT-5 has been launched in 2013, so the research related to the X-band SAR satellite image is required to increase the utilization of KOMPSAT-5. In this study, we generated a DEM(Digital Elevation Model) using X-band SAR satellite images based on three methods which are InSAR, radargrammetry and RPC(Rational Polynomial Coefficients), and evaluated the performance of each methods. The four stripmap mode TerraSAR-X images taken in Daejeon were used to generate DEM, and accuracy was evaluated using DEM by IKONOS RPC. As results, DEM produced by the InSAR showed the highest accuracy. Also, we knew that RPC could be effective method if you want to create a large area DEM which contains the various elevation.

• Journal of the Korean association of regional geographers
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• v.18 no.1
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• pp.1-16
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• 2012

As the tourists of ecotourism are increasing, the supply for detailed information on tourist attraction is also significantly increasing. As a result of survey given to tourists, it showed that they are more interested in natural ecological resources rather than history or culture among resources of ecotourism and pointed out that more information on the region needs to be supplemented. In order to provide accurate, detailed and standardized information to tourists, ecotourism resources were categorized as experience type from the position of consumer and ecological resource type. And the category of experience is again divided into 4 types - nature, education, communication and adventure. Moreover, after developing the web-based homepage for it, the research proposed the cases of Tae-an area and Ulleungdo Island. If the problems from test operation are supplemented, it is expected to suggest the standard of mobile based digital storytelling technology in the field of ecotourism.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.1
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• pp.77-82
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• 2014

SD memory cards are widely used in portable digital devices, and most of them exploit NAND flash memory as their storage, so that they have a feature of storing users' important data safely with low costs. In case of using NAND flash memory as storage, however, there is no method to store users' data if memory capacity is insufficient when transferring a large volume of data. This paper proposes a virtual SD memory card system. It used a SD memory card device driver to process data requested from a host by exploiting external storage rather than by exploiting flash memory as a memory core for storing data to the SD memory card. For experiment, it used the FPGA-based SD card slave controller IP on the SMC controller with a S3C2450 ARM CPU to test.