• Radiation Oncology Journal
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• v.21 no.2
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• pp.167-173
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• 2003

Purpose: The purpose of this study was to evaluate whether a GafChromic film applied to stereotactic radiosurgery with a linear accelerator could provide information on the value for acceptance testing and quality control on the absolute dose and relative dose measurements and/or calculation of treatment planning system. Materials and methods: A spherical acrylic phantom, simulating a patient's head, was constructed from three points. The absolute and relative dose distributions could be measured by inserting a GafChromic film into the phantom. We tested the use of a calibrated GafChromic film (MD-55-2, Nuclear Associate, USA) for measuring the optical density. These measurements were achieved by irradiating the films with a dose of 0-112 Gy employing 6 MV photon. To verify the accuracy of the prescribed dose delivery to a target isocenter using a five arc beams (irradiated in 3 Gy per one beam) setup, calculated by the Linapel planning system the absolute dose and relative dose distribution using a GafChromic film were measured. All the irradiated films were digitized with a Lumiscan 75 laser digitizer and processed with the RIT113 film dosimetry system. Results: We verified the linearity of the Optical Density of a MD-55-2 GafChromic film, and measured the depth dose profile of the beam. The absolute dose delivered to the target was close to the prescribed dose of Linapel within an accuracy for the GafChromic film dosimetry (of $\pm$3$\%$), with a measurement uncertainty of $\pm$1 mm for the 50$\~$90$\%$ isodose lines. Conclusion: Our results have shown that the absolute dose and relative dose distribution curves obtained from a GafChromic film can provide information on the value for acceptance. To conclude the GafChromic flim is a convenient and useful dosimetry tool for linac based radiosurgery.

• Progress in Medical Physics
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• v.14 no.2
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• pp.131-140
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• 2003

As the importance of accuracy in measurings of 3-D anatomical structures continues to be stressed, an objective and quantitative of assessing image quality and accuracy of 3-D volume-rendered images is required. The purpose of this study was to evaluate the quantitative accuracy of 3-D rendered images obtained with MDCT, scanned at various scanning parameters (scan modes, slice thicknesses and reconstruction slice thickness). Twelve clinically significant points that play an important role for the craniofacial bone in plastic surgery and dentistry were marked on the surface of a dry human skull. The direct distances between the reference points were defined as gold standards to assess the measuring errors of 3-D images. Then, we scanned the specimen with acquisition parameters of 300 mA, In kVp, and 1.0 sec scan time in axial and helical scan modes (pitch 3:1 and 6:1) at 1,25 mm, 2.50 mm, 3.75 mm and 5.00 mm slice thicknesses. We performed 3-D visualizations and distance measurements with volumetric analysis software and statistically evaluated the quantitative accuracy of distance measurements. The accuracy of distance measurements on the 3-D images acquired with 1.25, 2.50, 3,75 and 5.00 mm slice thickness were 48%, 33%, 23%, 14%, respectively, and those of the reconstructed 1.25 mm were 53%, 41%, 43%, 36% respectively. Meanwhile, there were insignificant statistical differences (P-value<0.05) in the accuracy of the distance measurements of 3-D images reconstructed with 1.25 mm thickness. In conclusion, slice thickness, rather than scan mode, influenced the quantitative accuracy of distance measurements in 3-D rendered images with MDCT. The quantitative analysis of distance measurements may be a useful tool for evaluating the accuracy of 3-D rendered images used in diagnosis, surgical planning, and radiotherapeutic treatment.

• Journal of Korea Port Economic Association
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• v.32 no.4
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• pp.73-87
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• 2016

The purpose of this study is to investigate the empirical results of Analytic Hierarchy Process/Data Envelopment Analysis-Assurance Region(AHP/DEA-AR) by using multiple regression analysis during the period of 2009-2012 with 5 inputs (number of gantry cranes, number of berth, berth length, terminal yard, and mean depth) and 2 outputs (container TEU, and number of direct calling shipping companies). Assurance Region(AR) is the most important tool to measure the efficiency of seaports, because individual seaports are characterized in terms of inputs and outputs. Traditional AHP and multiple regression analysis techniques have been used for measuring the AR. However, few previous studies exist in the field of seaport efficiency measurement. The main empirical results of this study are as follows. First, the efficiency ranking comparison between the two models (AHP/DEA-AR and multiple regression) using the Wilcoxon signed-rank test and Mann-Whitney signed-rank sum test were matched with the average level of 84.5 % and 96.3% respectively. When data for four years are used, the ratios of the significant probability are decreased to 61.4% and 92.5%. The policy implication of this study is that the policy planners of Korean port should introduce AHP/DEA-AR and multiple regression analysis when they measure the seaport efficiency and consider the port investment for enhancing the efficiency of inputs and outputs. The next study will deal with the subjects introducing the Fuzzy method, non-radial DEA, and the mixed analysis between AHP/DEA-AR and multiple regression analysis.

• Sleep Medicine and Psychophysiology
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• v.12 no.1
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• pp.32-38
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• 2005

Objectives: Obstructive sleep apnea syndrome (OSAS) has drawn increasing attention as medical community has become to be aware of its co-morbidities and complications, especially cardiovascular complications and excessive daytime sleepiness with accident proneness. As of now, polysomnography is the standard tool to diagnose sleep apnea and estimate the treatment validity. However, its being rather expensive and inconvenient, alternate diagnostic tools have been proposed including wrist actigraphy. So far, actigraphies have been adopted usefully to field-survey sleep apnea prevalence. In this study, we attempted in a sleep laboratory setting to assess the supplemental value of actigraphy in diagnosing OSAS. Methods: This study was done at the Division of Sleep Studies, the Seoul National University Hospital. Thirty-seven clinically suspected cases of OSAS underwent the one-night polysomnography, simultaneously wearing an actigraphy on non-dominant wrist. We analyzed the data of 27 polysomnographically-proven OSAS patients (male：female 20： 7；age $47.6{\pm}12.9$ years old；age range 23 to 72 years) with no other sleep disorders. We calculated RDI (respiratory disturbance index) from the polysomnography data and FI (fragmentation index) from the actigraphy data. Pearson correlation was calculated in order to compare FI with RDI and to evaluate the supplemental diagnostic value of the actigraphy. Results: Mean total sleep time on polysomnography was $401.4{\pm}57.8\;min$ (range of 274.0 to 514.1 min). Mean RDI was $21.7{\pm}20.4/hour$. Mean FI was $21.9{\pm}13.0/hour$. RDI and FI showed significant correlation (r=0.55, p<0.01). Conclusions: Wrist actigraphy in OSAS patients generates a comparable outcome to polysomnography, in measuring the nocturnal sleep fragmentation. The actigraphy could be used supplementally in inpatients, outpatients, and field survey subjects, if polysomnography is unavailable or impossible. In follow-ups related with nasal CPAP (continuous positive airway pressure), upper airway surgery, and oral appliance in OSAS patients, the actigraphy might play a more dominant role in the future.

• Journal of Intelligence and Information Systems
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• v.22 no.4
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• pp.123-138
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• 2016

This study investigates intents of acquisitions in information technology industries. Mergers and acquisitions are a strategic decision at corporate-level and have been an important tool for a firm to grow. Plenty of firms in information technology industries have acquired startups to increase production efficiency, expand customer base, or improve quality over the last decades. For example, Google has made about 200 acquisitions since 2001, Cisco has acquired about 210 firms since 1993, Oracle has made about 125 acquisitions since 1994, and Microsoft has acquired about 200 firms since 1987. Although there have been many existing papers that theoretically study intents or motivations of acquisitions, there are limited papers that empirically investigate them mainly because it is challenging to measure and quantify intents of M&As. This study examines the intent of acquisitions by measuring specific intents for M&A transactions. Using our measures of acquisition intents, we compare the intents by four acquisition types: (1) the acquisition where a hardware firm acquires a hardware firm, (2) the acquisition where a hardware firm acquires a software/IT service firm, (3) the acquisition where a software/IT service firm acquires a hardware firm, and (4) the acquisition where a software /IT service firm acquires a software/IT service firm. We presume that there are difference in reasons why a hardware firm acquires another hardware firm, why a hardware firm acquires a software firm, why a software/IT service firm acquires a hardware firm, and why a software/IT service firm acquires another software/IT service firm. Using data of the M&As in US IT industries, we identified major intents of the M&As. The acquisition intents are identified based on the press release of M&A announcements and measured with four categories. First, an acquirer may have intents of cost saving in operations by sharing common resources between the acquirer and the target. The cost saving can accrue from economies of scope and scale. Second, an acquirer may have intents of product enhancement/development. Knowledge and skills transferred from the target may enable the acquirer to enhance the product quality or to expand product lines. Third, an acquirer may have intents of gain additional customer base to expand the market, to penetrate the market, or to enter a foreign market. Fourth, a firm may acquire a target with intents of expanding customer channels. By complementing existing channel to the customer, the firm can increase its revenue. Our results show that acquirers have had intents of cost saving more in acquisitions between hardware companies than in acquisitions between software companies. Hardware firms are more likely to acquire with intents of product enhancement or development than software firms. Overall, the intent of product enhancement/development is the most frequent intent in all of the four acquisition types, and the intent of customer base expansion is the second. We also analyze our data with the classification of production-side intents and customer-side intents, which is based on activities of the value chain of a firm. Intents of cost saving operations and those of product enhancement/development can be viewed as production-side intents and intents of customer base expansion and those of expanding customer channels can be viewed as customer-side intents. Our analysis shows that the ratio between the number of customer-side intents and that of production-side intents is higher in acquisitions where a software firm is an acquirer than in the acquisitions where a hardware firm is an acquirer. This study can contribute to IS literature. First, this study provides insights in understanding M&As in IT industries by answering for question of why an IT firm intends to another IT firm. Second, this study also provides distribution of acquisition intents for acquisition types.

• KSBB Journal
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• v.19 no.2
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• pp.93-97
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• 2004

We investigate the effect of enzyme pretreatment using protease, carbohydrase, and lipase on improvement of sludge treatment efficiency by measuring SCOD and TCOD. The enzyme-pretreatment increases SCOD of excess sludge. In addition, the amount of sludge reduction during digestion, in terms of SCOD and TCOD, are enhanced by enzyme-pretreatment. Among pretense, carbohydrase, and lipase, pretense showed the best enhancement of the sludge treatment efficiency. Sludge digestion followed by ozone and enzyme treatments showed more effective sludge treatment when compared with ozone treatment alone. Therefore, we expect that enzyme pretreatment can be used as a useful tool for enhancing the sludge treatment efficiency.

• Journal of Korea Port Economic Association
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• v.26 no.4
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• pp.188-206
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• 2010

Data Envelopment Analysis(DEA) is an operations research-based method for measuring the performance efficiency of decision units that are characterized by multiple inputs and outputs. DEA has been applied successfully as a performance evaluation tool in many fields. However, it has not been extensively applied in the shipbuilding industry. This paper applied the input-oriented DEA model, and Malmquist indices to the 7 shipbuilding firms to measure the efficiency and productivity changes during the period of 2004 to 2009. The Malmquist indices will be decomposed into three components such as pure efficiency change, scale efficiency change, and technical change. The empirical results show the following findings. First, the DEA findings indicate that main source of inefficiency is scale rather than pure technical. Second, the Malmquist indices show that an overall decrease in productivity.

• Journal of East-West Nursing Research
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• v.5 no.1
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• pp.36-49
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• 2000

This study aims to provide the fundamental data for substantial nursing intervention in the elderly through a comparative appreciation on family support, self-esteem, and health status between the institutionalized elderly people and the home-staying ones. The subjects of this study are the institutionalized 108 elderly people of E and C Public Homes and the home-staying 109 elderly ones of O-Nho In Jeong(a kind of public recreational facilities for the aged) over the age of 65. The instruments for this research are based upon the tool(11 items, 5 points for each) for measuring family support developed by Choi, Young Hee(1984), a self-esteem scale done by Rosenberg (1965), the tools(20 items) for checking the health status of the elderly done by Lee, Young-Ja(1989). The sampling for this study has been carried on from July, 2000 until November, 2000. Questionnaire data were drawn up by personal interviews. The analyses of collected data are based on general characteristics calculated at the rate of 100 percentage to the average, t-test, ANOVA(some difference on a level with p<.05 being subsequently confirmed by DMR) for family support, self-esteem and health status, and Pearson Correlation to verify the hypothetical correlation among the subjects' family support, self-esteem and health status. The results of this study are as follows: 1. The difference between two groups in the light of family support, self-esteem and health status. (1) Family support - The rate of the family support that the institutionalized elderly people perceive turned out to be 22.13, that of the home-staying ones 30.99. (2) Self-esteem - The rate of the self-esteem that the former perceives proved to be 25.59, that of the latter 32.28. (3) Health Status - The rate of the health status that the former perceives turned out to be 39.67, that of the latter 51.60. 2. Family support, self-esteem, health status in terms of demographic characteristic (1) Family support - The group of institutionalized elderly people shows a tendency to be chiefly influenced by the death or life of the spouse and the number of the children; the group of the home staying ones to be chiefly influenced by the educational level (2) Self-esteem - The group of institutionalized elderly people shows a tendency to be chiefly influenced by educational level; the group of the home staying ones to be chiefly influenced by the amount of pocket money, the pocket money provider and the family main supporter. (3) Health Status - The group of institutionalized elderly people shows a tendency to be chiefly influenced by educational level; the group of the home staying ones to be chiefly influenced by age, the death or life of spouse, religion, and the educational level. 3. Correlation among family support, self-esteem, and health status The rate of correlation between family support and health status proved to be the highest (r=.549). After came the rate of correlation between health status and self-esteem, which turned out to be(r=.506). The last came the rate of correlation between family support and self-esteem, which proved to be(r=.406). According to this study, there is a conspicuously close correlation among family support, self-esteem, and health status for the elderly. Thus, it would be indispensable to seek out a variety of nursing intervention ways how the elderly could promote family support, self-esteem, and health status.

• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.388-396
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• 1998

Background: Etiologic diagnosis of pleural effusion is usually made by clinical characteristics, pleural fluid analysis and pleural biopsy. But, despite careful diagnostic study, the cause of pleural effusion cannot be found in about 20 percent of patients, especially in loculated pleural effusions. Tuberculous pleurisy is one of the most common cause of pleural effusion in Korea. But, pleural fluid culture for Mycobacterium tuberculosis are positive in only 20 to 30 percent of patients and typical pleural biopsy finding in less than 50 percent of patients with this disease. In recent studies, adenosine deaminse(ADA) and its isoenzymes were proposed to be a useful diagnostic tool for differential diagnosis of pleural effusion. We investigated the pattern of ADA and its iscenzyme activities in various cause of pleural effusions to evaluate the diagnostic value of measuring ADA and its isoenzymes. Method: We measured total ADA and its isoenzyme activities in pleural fluid and serum from 54 patients with pleural effusion(25 tuberculous pleural effusion, 10 parapneumonic effusion, 14 malignant pleural effusion, 5 transudative pleural effusion), including 5 loculated tuberculous pleural effusions and 6 loculated parapneumonic effusions. Total ADA activity was measured by the spectrophotometric method and ADA2 isoenzyme activity was measured with same method using EHNA, potent inhibitor of ADA1 isoenzyme activity. Result: Total ADA activity of tuberculous pleural effusion was higher than malignant pleural effusion(p<0.01), but no significant difference was found between tuberculous pleural effusion and parapneumonic effusion(tuberculous pleural effusion: $148.9{\pm}89.9IU/L$, parapneumonic effusion: $129.0{\pm}119.4IU/L$, malignant pleural effusion: $48.7 {\pm}39.7IU/L$). Percentage of ADA2 activity to total ADA activity(ADA2%) of pleural effusion of tuberculous pleurisy was higher than parapneumonic effusion(p<0.05). but no significant difference was found between tuberculous pleural effusion and malignant pleural effusion(tuberculous pleural effusion: $57.2{\pm}10.7%$, parapneumonic effusion: $35.9{\pm}17.8%$, malignant pleural effusion: $60.7{\pm}4.1%$). In loculated pleural effusion, ADA2% of tuberculous pleural effusion was higher than parapneumonic effusion(tuberculous pleural effusion: $53.3{\pm}3.9%$, parapneumonic effusion: $27.8{\pm}7.9%$). Conclusion: Measurement of ADA isoenzyme activity is useful for differentiating tuberculous pleural effusion from parapneumonic effusion, especially in loculated pleural effusion.

• Journal of radiological science and technology
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• v.32 no.4
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• pp.419-426
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• 2009

Purpose : The aim of this study was to evaluate the difference of bone mineral density according to distal radius rotation and to develop the supporting tool to measure rotation angles. Materials and Methods : CT scanning and the measurement of BMD by DXA of the appropriate position of the forearm were performed on 20 males. Twenty healthy volunteers without any history of operations, anomalies, or trauma were enrolled. The CT scan was used to evaluate the cross sectional structure and the rotation angle on the horizontal plane of the distal radius. The rotational angle was measured by the m-view program on the PACS monitor. The DXA was used in 20 dried radii of cadaveric specimens in pronation and supination with five and ten degrees, respectively, including a neutral position (zero degrees) to evaluate the changes of BMD according to the rotation. Results : The mean rotation angle of the distal radius on CT was 7.4 degrees of supination in 16 cases (80%), 3.3 degrees of pronation in three cases (15%), and zero degree of neutral in one case (9%), respectively. The total average rotation angle in 20 people was 5.4 degrees of supination. In the cadaveric study, the BMD of the distal radius was different according to the rotational angles. The lowest BMD was obtained at 3.3 degrees of supination. Conclusion : In the case of the measurement of BMD in the distal radius with a neutral position, the rotational angle of the distal radius is close to supination. Pronation is needed for the constant measurement of BMD in the distal radius with the rotation angle measuring at the lowest BMD and about five degrees of pronation of the distal radius is recommended.