• Journal of radiological science and technology
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• v.39 no.4
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• pp.651-660
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• 2016

Due to recent population aging, the number of check-up for senior citizens has increased steadily. According to this trend, the market size of dental X-ray equipment and the number of approval and review for these devices have simultaneously increased. The technical document of medical device is required for approval and review for medical device, and medical device companies needs to have work comprehension and expertise, as the document needs to include the overall contents such as performances, test criteria, etc.. Yet, since most of domestic manufacturers or importers of medical devices are small businesses, it is difficult for them to recruit professional manpower for approval of medical devices, and submission of inaccurate technical documents has increased. These problems lead to delay of the approval process and to difficulties in quick entering into the market. Especially, the Ministry of Food and Drug safety (MFDS) standards of a dental extra-oral X-ray equipment, a dental intra-oral X-ray equipment, an arm-type computed tomography, and a portable X-ray system have been recently enacted or not. this guideline of dental X-ray equipment adjusting revised standards was developed to help relative companies and reviewers. For this study, first, the methods to write technical document have been reviewed with revised international and domestic regulations and system. Second, the domestic and foreign market status of each item has been surveyed and analyzed. Third, the contents of technical documents already approved by MFDS have been analyzed to select the correct example, test items, criteria, and methods. Finally, the guideline has been developed based on international and domestic regulation, through close review of a consultative body composed of academic, industrial, research institute and government experts.

• The Korean Journal of Nuclear Medicine
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• v.23 no.2
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• pp.175-181
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• 1989

Visual assessment of regional wall motion abnormality (RWMA) by gated blood pol scan (GBPS) serves as an useful parameter in the diagnosis, functional evaluation, and follow up in various clinical settings, but are still subject to some inherent limitations. On important problem may be the interobserver as well as intraobsever variation that may well be present due to the subjective nature of the interpretations. This study was carried out to determine the reliability and reproducibility of visual assessments made in GBPSs, and to observe the degree to which the results would be influenced by observer variation. Fifty two patients with coronary heart disease had resting GBPS and contrast ventriculography within 4 days appall. Contrast ventriculography-showed normal wall motion in 6 patients and the remaining 46 had RWMA in one or more segments. The anterior and left anterolateral views of all 52 GBPSs were analyzed by three independent observers, who selected from 5 scales, their level of confidence that there was RWMA in that segment. Reciever operating characteristic (ROC) curves for each analysis was plotted and the area under the curve $(\theta)$ was used as a parameter representing each observer's performance in his interpretations. The findings of contrast ventriculographies were used as the standard for RWMA. The apical and inferoapical segments showed the best correlation with contrast ventriculography ($\theta=0.90-0.94$, 0.81-0.94, respectively), and the inferior wall showed the poorest correlation $(\theta=0.70-0.74)$. The interpretations of the inferior, septal, apical, and posteroinferior, segments showed no difference between the observers, but there was significantly better performance in assessment by observer A compared to that by B or C for the anterolateral segments ($\theta=0.87$, 0.78, 0.76, respectively. p<0.01 for A vs B, p<0.05 for A vs C), as well as when all segments were considered altogether ($\theta=0.88$, 0.83, 0.82, respectively. both p<0.05). This was also true for the infero-apical segment between A and C ($\theta=0.09$, 0.81, p<0.05). The intraobserver variation, however, did not appear significant, with only the inferior segment for observer B showing any significant difference when observer A and B repeated the analysis 10 days latter. There was no difference in assessing dyskinesia, with all observers showing a high performance ($\theta=0.98$, 0.87, 0.97, respectively). The visual assessment of left ventricular ejection fraction by all three observers correlated well with the calculated value from a semiautomated method (Spearman's r = 0.91, 0.83, 0.83. p<0.01, p<0.05, p < 0.05). The assessment of LV and RV size also correlated well between the three observers (Kendall's w = 0.80, 0.51, p<0.01 for both left and right ventricles). The above findings suggest that RWMA visually assessed by GBPS correlates well with that done by contrast ventriculography. And although the observer's experience or skill may influence the results in certain segments, visual analysis of GBPS may serve as a reliable and reproducible means for evaluating ventricular function.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.4
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• pp.176-184
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• 2011

Cold air on sloping surfaces flows down to the valley bottom in mountainous terrain at calm and clear nights. Based on the assumption that the cold air flow may be the same as the water flow, current models estimate temperature drop by regarding the cold air accumulation at a given location as the water-like free drainage. At a closed catchment whose outlet is blocked by man-made obstacles such as banks and roads, however, the water-like free drainage assumption is no longer valid because the cold air accumulates from the bottom first. We developed an empirical model to estimate quantitatively the effect of cold pool on nocturnal temperature in a closed catchment. In our model, a closed catchment is treated like a "vessel", and a digital elevation model (DEM) was used to calculate the maximum capacity of the cold pool formed in a closed catchment. We introduce a topographical variable named "shape factor", which is the ratio of the cold air accumulation potential across the whole catchment area to the maximum capacity of the cold pool to describe the relative size of temperature drop at a wider range of catchment shapes. The shape factor is then used to simulate the density profile of cold pool formed in a given catchment based on a hypsometric equation. The cold lake module was incorporated with the existing model (i.e., Chung et al., 2006), generating a new model and predicting distribution of minimum temperature over closed catchments. We applied this model to Akyang valley (i.e., a typical closed catchment of 53 $km^2$ area) in the southern skirt of Mt. Jiri National Park where 12 automated weather stations (AWS) are operational. The performance of the model was evaluated based on the feasibility of delineating the temperature pattern accurately at cold pool forming at night. Overall, the model's ability of simulating the spatial pattern of lower temperature were improved especially at the valley bottom, showing a similar pattern of the estimated temperature with that of thermal images obtained across the valley at dawn (0520 to 0600 local standard time) of 17 May 2011. Error in temperature estimation, calculated with the root mean square error using the 10 low-lying AWSs, was substantially decreased from $1.30^{\circ}C$ with the existing model to $0.71^{\circ}C$ with the new model. These results suggest the feasibility of the new method in predicting the site-specific freeze and frost warning at a closed catchment.

• Journal of Chest Surgery
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• v.40 no.10
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• pp.674-679
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• 2007

Background: Surgical resection is accepted widely as the standard therapy for complete resectable pulmonary metastases. The number of cases of pulmonary metastasectomy and its survival rate is increasing due to the development of the therapeutic modalities. We attempted to analyze the survival rate and prognosis factors of pulmonary metastasectomy during the last 10 years. Material and Method: We retrospectively analyzed the data of 89 patients who underwent 96 procedures of pulmonary metastasectomy between January 1996 and December 2005. The factors that may influence the long term prognosis such as completeness of resection, the type of primary cancer, the disease-free interval, the number and size of metastasis and the laterality were investigated. Result: There was no operative mortality. The mean disease free interval (DFI) was $29.6{\pm}27.9$ months and there were 3 cases of synchronous metastasis (3.4%). The overall 3, 5 and 10 year survival rate was 52.5%, 32.1% and 20.7%, respectively. The median survival time was 38 months. The 5-year survival rate according to the IRLM appraisal was 63.5%, 33.3%, 22.1% and 0% for stage I, II, III and IV, respectively Univariate analysis showed a better prognosis for patients with a disease free interval of 36 months or more, unilateral metastasis and 4 or less metastases. Conclusion: The survival rate for completely resectable pulmonary metastasectomy was favorable. The disease free interval, laterality and the number of metastasis were the prognosis factors.

• Fiber Technology and Industry
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• v.2 no.4
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• pp.490-508
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• 1998

One of the latest fields of research in the area of output devices is tactual display devices [13,31]. These tactual or haptic devices allow the user to receive haptic feedback output from a variety of sources. This allows the user to actually feel virtual objects and manipulate them by touch. This is an emerging technology and will be instrumental in enhancing the realism of wearable augmented environments for certain applications. Tactual displays have previously been used for scientific visualization in virtual environments by chemists and engineers to improve perception and understanding of force fields and of world models populated with the impenetrable. In addition to tactual displays, the use of wearable audio displays that allow sound to be spatialized are being developed. With wearable computers, designers will soon be able to pair spatialized sound to virtual representations of objects when appropriate to make the wearable computer experience even more realistic to the user. Furthermore, as the number and complexity of wearable computing applications continues to grow, there will be increasing needs for systems that are faster, lighter, and have higher resolution displays. Better networking technology will also need to be developed to allow all users of wearable computers to have high bandwidth connections for real time information gathering and collaboration. In addition to the technology advances that make users need to wear computers in everyday life, there is also the desire to have users want to wear their computers. In order to do this, wearable computing needs to be unobtrusive and socially acceptable. By making wearables smaller and lighter, or actually embedding them in clothing, users can conceal them easily and wear them comfortably. The military is currently working on the development of the Personal Information Carrier (PIC) or digital dog tag. The PIC is a small electronic storage device containing medical information about the wearer. While old military dog tags contained only 5 lines of information, the digital tags may contain volumes of multi-media information including medical history, X-rays, and cardiograms. Using hand held devices in the field, medics would be able to call this information up in real time for better treatment. A fully functional transmittable device is still years off, but this technology once developed in the military, could be adapted tp civilian users and provide ant information, medical or otherwise, in a portable, not obstructive, and fashionable way. Another future device that could increase safety and well being of its users is the nose on-a-chip developed by the Oak Ridge National Lab in Tennessee. This tiny digital silicon chip about the size of a dime, is capable of 'smelling' natural gas leaks in stoves, heaters, and other appliances. It can also detect dangerous levels of carbon monoxide. This device can also be configured to notify the fire department when a leak is detected. This nose chip should be commercially available within 2 years, and is inexpensive, requires low power, and is very sensitive. Along with gas detection capabilities, this device may someday also be configured to detect smoke and other harmful gases. By embedding this chip into workers uniforms, name tags, etc., this could be a lifesaving computational accessory. In addition to the future safety technology soon to be available as accessories are devices that are for entertainment and security. The LCI computer group is developing a Smartpen, that electronically verifies a user's signature. With the increase in credit card use and the rise in forgeries, is the need for commercial industries to constantly verify signatures. This Smartpen writes like a normal pen but uses sensors to detect the motion of the pen as the user signs their name to authenticate the signature. This computational accessory should be available in 1999, and would bring increased peace of mind to consumers and vendors alike. In the entertainment domain, Panasonic is creating the first portable hand-held DVD player. This device weight less than 3 pounds and has a screen about 6' across. The color LCD has the same 16:9 aspect ratio of a cinema screen and supports a high resolution of 280,000 pixels and stereo sound. The player can play standard DVD movies and has a hour battery life for mobile use. To summarize, in this paper we presented concepts related to the design and use of wearable computers with extensions to smart spaces. For some time, researchers in telerobotics have used computer graphics to enhance remote scenes. Recent advances in augmented reality displays make it possible to enhance the user's local environment with 'information'. As shown in this paper, there are many application areas for this technology such as medicine, manufacturing, training, and recreation. Wearable computers allow a much closer association of information with the user. By embedding sensors in the wearable to allow it to see what the user sees, hear what the user hears, sense the user's physical state, and analyze what the user is typing, an intelligent agent may be able to analyze what the user is doing and try to predict the resources he will need next or in the near future. Using this information, the agent may download files, reserve communications bandwidth, post reminders, or automatically send updates to colleagues to help facilitate the user's daily interactions. This intelligent wearable computer would be able to act as a personal assistant, who is always around, knows the user's personal preferences and tastes, and tries to streamline interactions with the rest of the world.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.12C
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• pp.1288-1298
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• 2002

To implement elliptic curve cryptosystem in GF(2$\^$m/) at high speed, a fast divider is required. Although bit-parallel architecture is well suited for high speed division operations, elliptic curve cryptosystem requires large m(at least 163) to support a sufficient security. In other words, since the bit-parallel architecture has an area complexity of 0(m$\^$m/), it is not suited for this application. In this paper, we propose a new serial-in serial-out systolic array for computing division operations in GF(2$\^$m/) using the standard basis representation. Based on a modified version of tile binary extended greatest common divisor algorithm, we obtain a new data dependence graph and design an efficient bit-serial systolic divider. The proposed divider has 0(m) time complexity and 0(m) area complexity. If input data come in continuously, the proposed divider can produce division results at a rate of one per m clock cycles, after an initial delay of 5m-2 cycles. Analysis shows that the proposed divider provides a significant reduction in both chip area and computational delay time compared to previously proposed systolic dividers with the same I/O format. Since the proposed divider can perform division operations at high speed with the reduced chip area, it is well suited for division circuit of elliptic curve cryptosystem. Furthermore, since the proposed architecture does not restrict the choice of irreducible polynomial, and has a unidirectional data flow and regularity, it provides a high flexibility and scalability with respect to the field size m.

• Journal of Life Science
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• v.22 no.11
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• pp.1456-1462
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• 2012

Sorafenib is a multikinase inhibitor and an oral anticancer drug approved for the treatment of patients with advanced renal cell carcinoma and those with unresectable hepatocellular carcinoma. The purpose of this study was to develop an efficient method of the determination of sorafenib in human plasma using tandem mass spectrometry coupled with liquid chromatography (LC/MS/MS) and validate the method by the guidelines of the Korean Food and Drug Administration (KFDA). Plasma samples ($100{\mu}l$) were added with chlorantraniliprole as an internal standard and then mixed with the 0.1% formic acid-containing extraction solution composed of isopropyl alcohol and ethyl acetate (1:4, v/v). After centrifugation, the supernatant was concentrated at $45^{\circ}C$ under negative pressure and centrifugal force. The residue was reconstituted with a mobile phase and injected into the HPLC instrument using a reverse phase Waters XTerra$^{TM}$ C18 column (particle size $3.5{\mu}m$). Liquid chromatography was carried out within the run time of 5 min using a mobile phase composed of buffer (0.1% formic acid and 10 mM ammonium formate), methanol, and acetonitrile (1:6:3, v/v/v). The analytes were monitored by tandem mass spectrometry in the multiple reaction monitoring method programmed to detect sorafenib at 'm/z 465.2 ${\rightarrow}$ 252.5' and chlorantraniliprole at 'm/z 484.4 ${\rightarrow}$ 286.2' with positive electrospray ionization mode ($ES^+$). The result showed the proper linearity ($r^2$ > 0.99) over the range of 2,000-5,000 ng/ml with good accuracy (90.7-103.9%) and precision (less than 10%). The newly developed method using LC/MS/MS was validated by the guideline of KFDA and identified as more sensitive compared to the previous methods.

• Herbal Formula Science
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• v.22 no.2
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• pp.63-76
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• 2014

Objectives : This study investigated the improvement effects of Pakistani (DF-a) and Chinese Ephedra herba-containing Gangjihwan (DF-b) on obesity in a high fat diet-fed obese mouse model. Methods : Eight-week-old C57BL/6N mice were divided into four groups: a normal lean group given a standard diet, an obese control group given a high fat diet, and DF-a and DF-b groups given a high fat diet with DF-a (80 mg/kg), and DF-b (80 mg/kg), respectively. After 8 weeks of treatment, body weight gain, feeding efficiency ratio, blood lipid markers, fat weight and histology were examined. Results : 1. Body weight gain and fat mass were significantly decreased in DF-a and DF-b groups compared with control. The extent of decreases was eminent in DF-a group. 2. Feeding efficiency ratio and circulating leptin concentration were significantly decreased in DF-a and DF-b groups compared with control, whereas circulating adiponectin concentration was increased in DF-a and DF-b groups compared with control. 3. Consistent with their effects on body weight gain and fat mass, circulating concentrations of triglyceride, glucose and insulin were decreased in DF-a and DF-b groups compared with control. 4. The size of adipocytes were decreased by DF-a and DF-b compared with control, whereas the adipocyte number per unit area was increased by them, suggesting that DF-a and DF-b decreased the number of large adipocytes. 5. Consistent with their effects on body weight gain, liver fibrosis was reduced in DF-a and DF-b groups compared with control. Conclusions : In conclusion, these results suggest that DF-a and DF-b not only decrease feeding efficiency ratio, plasma leptin concentration, and blood anti-obesity biomarkers, but also reduce fat mass, contributing to the improvement of obesity. DF-a and DF-b also inhibit liver fibrosis. In addition, these effects were similar between Pakistani Ephedra herba and Chinese Ephedra herba-containing Gangjihwan.

• Herbal Formula Science
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• v.22 no.2
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• pp.105-120
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• 2014

Objectives : This study was investigated the improvement effects of Gangjihwan (DF) and combination of Gangjihwan and Gamisochehwan (GSH) on obesity in a high fat diet-fed obese mouse model. Methods : Eight-week-old C57BL/6N mice were divided into four groups: a normal lean group given a standard diet, an obese control group given a high fat diet, and DF and DF+GSH groups given a high fat diet with DF (40 mg/kg), and DF+GSH (80 mg/kg), respectively. After 8 weeks of treatment, body weight gain, feeding efficiency ratio, blood lipid markers, fat weight and histology were examined. Results : 1. Body weight gain and fat mass were significantly decreased in DF and DF+GSH groups compared with control. The extent of decreases was eminent in DF+GSH group. 2. Feeding efficiency ratio and circulating concentration of leptin were decreased in DF and DF+GSH groups compared with control. These decreases were significant in DF+GSH group. 3. Consistent with their effects on body weight gain and fat mass, circulating concentrations of triglyceride, glucose and insulin were decreased in DF and DF+GSH groups compared with control. 4. The size of adipocytes was decreased by DF and DF+GSH compared with control, whereas the adipocyte number per unit area was increased by them, suggesting that DF and DF+GSH decreased the number of large adipocytes. 5. Consistent with their effects on body weight gain, liver fibrosis was also improved in DF and DF+GSH groups compared with control. Conclusions : In conclusion, these results suggest that DF and DF+GSH groups decrease feeding efficiency ratio, plasma leptin concentration, blood anti-obesity biomarkers and fat mass, improves body weight gain contributing to the inhibition of liver fibrosis. In addition, these effects were more effective in DF+GSH combination group than in DF-only group.

• Journal of the Korean association of regional geographers
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• v.7 no.1
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• pp.83-95
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• 2001

The purpose of this study is to examine that we can estimate land use by land values in 5 great cities. For this purpose, I calculated the percentage that each lot value makes up of the highest land values in the city as a indicator. I think this rate is very useful in the comparative study about many cities. At first, I set up four hypotheses based on my preceding studies. Hypothesis 1, the range of CBD can be estimated as having about 10% of the peak land values. Hypothesis 2, when the peak rate of concentric circle of land values seperated from CBD circle is about 30% of the peak land values, that is sub-CBD. Hypothesis 3, generally, a lot of having about 5% of the peak land values represents residential land commercial land use. Hypothesis 4, a lot of having about 3% of the peak land values represents only residential land use. The data on land values in five great cities were got from public notification on land values(1999) of the Ministry of Construction & Transportation. I selected highest lot values from many standard lot value in each Tong(the minimum administrative unit) in each cities. And I drew land values isopleth. Through that isopleth, I identified CBD cmd sub-CBD. Through the book of public notification on land values, I identified what land use are lots of having over 10%, about 5%, below 3% of the peak land values. As a result, we identified land use can be estimated by the percentage that each lot value makes up of the highest land values in the city. The bigger urban size becomes and the more stable land use becomes, the higher fitness of hypotheses becomes. The lowest degree of fitness about 4 hypotheses among 5 great cities showed in Inchon. Because Inchon lies adjacent to the greatest Seoul. The percentage that showed the lowest degree of fitness is 5% of the highest land values. The land use on lots of having about 5% of the peak land values is different from each other according to regional character in city.