• Journal of Chest Surgery
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• v.37 no.6
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• pp.524-529
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• 2004

Background: Since the Nuss procedure for the correction of pectus excavatum is in its early stage, there have been problems that need to be solved. We examined complications in a single-institute experience of the Nuss technique in order to develop possible solutions to prevent them. Material and Method: 335 consecutive patients, who underwent the modified Nuss procedure between August 1999 and October 2002, were studied retrospectively. Median age was 8 years (range 1 to 46). 264 patients (78.8%) were in pediatric group (age$\leq$15) and 71 patients (21.2%) were in adult group (age> 15). 193 patients (57.6%) had symmetric and 142 patients (42.4%) had asymmetric pectus configurations. Risk factors predicting postoperative complications were analyzed using multi-variate logistic regression. Result: Postoperative complication rates were 18.9% (61/335) in total patients. Frequent complications were pneumothorax 24 (7.5%), bar displacement 11 (3.4%), and wound seroma 10 (3.1%) in order. Early complications (within a month, 49 cases, 15.2%) were pneumothorax (n=23, 6.9%), wound seroma (n=12, 3.6%), and bar displacement (n=8, 2.4%). Late complications (after a month, 12 cases, 3.7%) were pericarditis and pericardial effusion (n=5, 1.5%), bar displacement (n=4, 1.2%), and hemothorax (n=3, 0.9%). Techniques were modified to prevent complications especially in bar shaping and fixation, which led to decrease complication rate in later experience (Operation Date 1: 15/51 (29.4%) vs Operation Date 2: 34/284 (12.0%), p=0.004). Grand Canyon type (eccentric long canal type) showed higher complication rate than other types (GC type: 12/30(40%) vs Others: 37/305 (12.1%), p<0.001). Major risk factors are severity of pectus (OR=2.88, p=0.038), Grand Canyon type (OR=2.82, p=0.044), and Op. Date 1 (OR=4.05, p=0.001). Conclusion: Major complications were related to severe eccentric type of pectus configuration (Grand Canyon type) and lack of surgeon's experience (Op. Date 1). Com-plication rate was reduced with accumulation of experience and advancement of surgical techniques. The Nuss procedure can be performed at a low risk of complications with our current technique.

• Economic and Environmental Geology
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• v.6 no.1
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• pp.29-64
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• 1973

A land resources survey in the semi-arid area, Mula in S. E. Spain, of $400km^2$ is compiled. The basic aim of the project is to investigate the intrinsic qualities of the land resources of the area by means of applying an integrated method of natural resources survey mainly concerning with analysis and synthesis of land complexes, each of them represents an area or a group of areas with similar patterns of landforms, soils and vegetation, based on a geomorphological approach. The area is characterized by a linear arrangement of relief pattern with an asymmetric homoclinal repetition of slope attitudes elongating WSW-ENE, dipping steeply on the NW sides and gently on the SE sides, which have been resulted from the post-Alpine folding of the Triassic to Cretaceous limestone, the Eocene limestone, the Oligocene sandstone and the lower Miocene limestone and marl, and the post-lower Miocene faulting, tilting and subsequent differential erosion of the Miocene sedimentary formations. An integrated body of information in geology, landforms, soils and vegetation, which are significantry interrelated as an environmental complex, has been obtained. Using this data, 26 land complexes developing on the various situations of landforms, such as folded mountain ranges, tilted tablelands, bevelled cuestas, degraded hill-lands associating with enormous foots lopes, undulating terrains and terraced or flat plains, have been differentiated, mapped and described. The soils of the area are mostly light colored calcic lithosols which have been derived dominantly from the marly parent materials and developed into remarkable slope catenas in some places depending on the relief conditions. The land uses of the area are mainly characterized by the perennially irrigated cultivation of citrus orchards along the terraced alluvial deposits fringing the Segura and Mula River, and the dry-land cereal cultivation on gentler slopes. Pioneer dry-land cultivations within the shrubs on steeper slopes are restricted to the unchannelled tributary drainage floors. The availability of water is a fundamental controlling factor for existence of native and cultivated vegetation as a whole, and a number of active processes including sheet wash and gully erosion, especially on the scarp slopes, are the other important factors to be considered in conservation and management of the land in the area.

• Journal of Chest Surgery
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• v.36 no.9
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• pp.646-650
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• 2003

Many surgical techniques for ischemic mitral regurgitation (IMR) have been used with their excellent results and advantages. Here, we report our simple posterior annuloplasty techniques using vascular graft strip with their early results. Material and Method: Twenty two patients (13 male) underwent the operations for IMR (excluding the papillary muscle rupture) from December 2001 to January 2003. Preoperative risk factors were low ejection fraction (<35％, n=9), hypertension (n=13), diabetes (n=9), and renal failure (Cr>2.5, n=4). The wide dissection beneath the both vena cavae and interatrial groove after bicaval cannulation enabled the easy exposure of mitral valve even in the small left atrium. After eight or nine interrupted sutures in posterior annulus for anchoring the 6 mm width vascular graft strip, symmetric (n=8) or asymmetric (n=14) annuloplasty were done. Combined surgeries were CABG (n=21), Dor procedures (n=3), tricuspid valve annuloplasty (n=1), Maze operation (n=1), and aorto-right subclavian artery bypass (n=1). Result: Except for one surgical mortality, all the patients were doing well and the mean grade of regurgitation was decreased from 2.95 to 0.88, however the ejection fraction had not changed significantly just before discharge. Post-operative valve function evaluated before discharge revealed no residual regurgitation in 8 (including 1 patient with mild stenosis due to over reduction), minimal in 11, mild in 2, and mild to moderate regurgitation in 1. One patient who had ischemic cardiomyopathy and renal failure died of the arrhythmia during the hemodialysis. Conclusion: These observations suggest that the annuloplasty with vascular graft strip could be a safe and cost effective techniques for ischemic mitral regurgitation. However, the long term evaluation for the mitral valve function should be defined for the final conclusion.

• Journal of Intelligence and Information Systems
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• v.17 no.1
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• pp.91-110
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• 2011

This paper analyzes the cases where the hotels have increased their services and enhanced their work process through IT solutions to cope with computerization globalization. Also the cases have been studies where national hotels use the CRM solution internally to respond effectively to customers requests, increase customer analysis, and build marketing strategies. In particular, this study discusses the introduction of the CRM solutions and CRM sales business and marketing services using a process for utilizing the presumed, CRM by introducing effective DEA(Data Envelopment Analysis). First, the comparison has done regarding the relative efficiency of L Company with the CCR model, then compared L Company's restaurants and facilities' effectiveness through BCC model. L Company reached a conclusion that it is important to precisely create and manage sales data which are the preliminary data for CRM, and for that reason it made it possible to save sales data generated by POS system on each sales performance database. In order to do that, it newly established Oracle POS system and LORIS POS system concerned with restaurants for food and beverage as well as rooms, and made it possible to stably generate and manage sales data and manage. Moreover, it set up a composite database to control comprehensively the results of work processes during a specific period by collecting customer registration information and made it possible to systematically control the information on sales performances. By establishing a system which unifies database and managing it comprehensively, impeccability of data has been greatly enhanced and a problem which generated asymmetric data could be thoroughly solved. Using data accumulated on the comprehensive database, sales data can be analyzed, categorized, classified through data mining engine imbedded in Polaris CRM and the results can be organized on data mart to provide them in the form of CRM application data. By transforming original sales data into forms which are easy to handle and saving them on data mart separately, it enabled acquiring well-organized data with ease when engaging in various marketing operations, holding a morning meeting and working on decision-making. By using summarized data at data mart, it was possible to process marketing operations such as telemarketing, direct mailing, internet marketing service and service product developments for perceived customers; moreover, information on customer perceptions which is one of CRM's end-products could feed back into the comprehensive database. This research was undertaken to find out how effectively CRM has been employed by comparing and analyzing the management performance of each enterprise site and store after introducing CRM to Hotel enterprises using DEA technique. According to the research results, efficiency evaluation for each site was calculated through input and output factors to find out comparative CRM system usage efficiency of L's Company four sites; moreover, with regard to stores, the sizes of workforce and budget application show a huge difference and so does the each store efficiency. Furthermore, by using the DEA technique, it could assess which sites have comparatively high efficiency and which don't by comparing and evaluating hotel enterprises IT project outcomes such as CRM introduction using the CCR model for each site of the related enterprises. By using the BCC model, it could comparatively evaluate the outcome of CRM usage at each store of A site, which is representative of L Company, and as a result, it could figure out which stores maintain high efficiency in using CRM and which don't. It analyzed the cases of CRM introduction at L Company, which is a hotel enterprise, and precisely evaluated them through DEA. L Company analyzed the customer analysis system by introducing CRM and achieved to provide customers identified through client analysis data with one to one tailored services. Moreover, it could come up with a plan to differentiate the service for customers who revisit by assessing customer discernment rate. As tasks to be solved in the future, it is required to do research on the process analysis which can lead to a specific outcome such as increased sales volumes by carrying on test marketing, target marketing using CRM. Furthermore, it is also necessary to do research on efficiency evaluation in accordance with linkages between other IT solutions such as ERP and CRM system.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.3
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• pp.157-165
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• 2006

The change of external/internal factors of the cell rquires specific biological functions to maintain life. Such functions encourage particular genes to jnteract/regulate each other in multiple ways. Accordingly, we applied a linear decomposition model IFSA, which derives hidden variables, called the 'expression mode' that corresponds to the functions. To interpret gene interaction/regulation, we used a cross-correlation method given an expression mode. Linear decomposition models such as principal component analysis (PCA) and independent component analysis (ICA) were shown to be useful in analyzing high dimensional DNA microarray data, compared to clustering methods. These methods assume that gene expression is controlled by a linear combination of uncorrelated/indepdendent latent variables. However these methods have some difficulty in grouping similar patterns which are slightly time-delayed or asymmetric since only exactly matched Patterns are considered. In order to overcome this, we employ the (IFSA) method of [1] to locate phase- and shut-invariant features. Membership scoring functions play an important role to classify genes since linear decomposition models basically aim at data reduction not but at grouping data. We address a new function essential to the IFSA method. In this paper we stress that IFSA is useful in grouping functionally-related genes in the presence of time-shift and expression phase variance. Ultimately, we propose a new approach to investigate the multiple interaction information of genes.

• The Journal of Korean Society for Radiation Therapy
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• v.16 no.1
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• pp.1-9
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• 2004

Purpose : The aim of this study is to investigate the properties of small field size and to measure the penumbra and central axis depth dose varying to the jaw setting and off axis distance for indicate this data to small field sizes radiation therapy. Material and methods : The percentage depth dose, beam profile and central axis output dose was measured by farmer type ion chamber and pinpoint chamber using Primart linac with 6MV energy. Beam quality and penumbra variations according to the central axis shift, from center to every 2cm outside increment, and field size, from $1{\times}1cm$ to $10{\times}10cm$ was investigated and compared with that of the standard geometrical condition's results Results : The differences of measured values between two ion chamber was about $37\%$ at 10cm depth with $1{\times}1cm$ field sizes but as field size increased this differences was diminished gradually. Measured data from various off axis distance with the different asymmetric collimations are not changed significantly but as size decreased the dose variation was increased and at $1{\times}1cm$ field size dose difference among off axis distance was as much as $13\%$, and as shallower the measured depth the central axis dose variations among the OAD was increased, penumbra was not changed noticeably depending on off axis distance but the percentage of penumbra from its initial field sizes was strongly dependant on field sizes and penumbra occupation rates of its own field sizes ranging from $6\%$ at $10{\times}10cm$ to $50\%$ at $1{\times}1cm$ field size. Conclusion : For imrt treatment, there are several numbers of different gentry angles with beams of nonuniform fluences are required and several complex factors involved. Among them the characteristics of beam output varying to the geometrical setting and design of collimators are of important to attaining a good treatment results. As mentioned in results the differences of measured values are changed significantly depends on ion chamber volume, depths and field size. For providing quality radiation treatment, especially at small field size, those factor's should have considering deliberately.

• KDI Journal of Economic Policy
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• v.12 no.2
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• pp.51-79
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• 1990

Research on technical efficiency, an important dimension of market performance, had received little attention until recently by most industrial organization empiricists, the reason being that traditional microeconomic theory simply assumed away any form of inefficiency in production. Recently, however, an increasing number of research efforts have been conducted to answer questions such as: To what extent do technical ineffciencies exist in the production activities of firms and plants? What are the factors accounting for the level of inefficiency found and those explaining the interindustry difference in technical inefficiency? Are there any significant international differences in the levels of technical efficiency and, if so, how can we reconcile these results with the observed pattern of international trade, etc? As the first in a series of studies on the technical efficiency of Korea's manufacturing industries, this paper attempts to answer some of these questions. Since the estimation of technical efficiency requires the use of plant-level data for each of the five-digit KSIC industries available from the Census of Manufactures, one may consture the findings of this paper as empirical evidence of technical efficiency in Korea's manufacturing industries at the most disaggregated level. We start by clarifying the relationship among the various concepts of efficiency-allocative effciency, factor-price efficiency, technical efficiency, Leibenstein's X-efficiency, and scale efficiency. It then becomes clear that unless certain ceteris paribus assumptions are satisfied, our estimates of technical inefficiency are in fact related to factor price inefficiency as well. The empirical model employed is, what is called, a stochastic frontier production function which divides the stochastic term into two different components-one with a symmetric distribution for pure white noise and the other for technical inefficiency with an asymmetric distribution. A translog production function is assumed for the functional relationship between inputs and output, and was estimated by the corrected ordinary least squares method. The second and third sample moments of the regression residuals are then used to yield estimates of four different types of measures for technical (in) efficiency. The entire range of manufacturing industries can be divided into two groups, depending on whether or not the distribution of estimated regression residuals allows a successful estimation of technical efficiency. The regression equation employing value added as the dependent variable gives a greater number of "successful" industries than the one using gross output. The correlation among estimates of the different measures of efficiency appears to be high, while the estimates of efficiency based on different regression equations seem almost uncorrelated. Thus, in the subsequent analysis of the determinants of interindustry variations in technical efficiency, the choice of the regression equation in the previous stage will affect the outcome significantly.

• Korean Journal of Ecology and Environment
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• v.57 no.1
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• pp.39-50
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• 2024

In ecosystems within limited resources, interspecific competition is inevitable, often leading to the competitive exclusion of inferior species. This study aims to provide foundational information for the conservation and restoration management of Microphysogobio rapidus by evaluating species' ecological response to biological factors within its habitat. To understand this relationship, we collected food web organisms from site where M. rapidus coexist with Microphysogobio yaluensis, a specie ecologically similar to M. rapidus, and evaluated the trophic levels (TL), isotopic niche space (INS), and the overlap of INS among fishes within the habitat using stable isotope analysis. Our analysis revealed that the M. rapidus exhibited a higher TL than M. yaluensis, with TL of 2.6 and 2.4, respectively. M. yaluensis exhibited a broad INS, significantly influencing the feeding characteristics of most fish. Conversely, M. rapidus showed a narrow INS and asymmetric feeding relationships with other species, in habitats with high competition levels. This feeding characteristics of M. rapidus indicate that the increase in competitors sharing the similar resources lead to a decrease in available resources and, consequently, is expected to result in a decrease in their density.

• Journal of Distribution Research
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• v.16 no.2
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• pp.119-138
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• 2011

Internet commerce has been growing at a rapid pace for the last decade. Many firms try to reach wider consumer markets by adding the Internet channel to the existing traditional channels. Despite the various benefits of the Internet channel, a significant number of firms failed in managing the new type of channel. Previous studies could not cleary explain these conflicting results associated with the Internet channel. One of the major reasons is most of the previous studies conducted analyses under a specific market condition and claimed that as the impact of Internet channel introduction. Therefore, their results are strongly influenced by the specific market settings. However, firms face various market conditions in the real worlddensity and disutility of using the Internet. The purpose of this study is to investigate the impact of various market environments on a firm's optimal channel strategy by employing a flexible game theory model. We capture various market conditions with consumer density and disutility of using the Internet.