• Tuberculosis and Respiratory Diseases
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• v.44 no.2
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• pp.309-320
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• 1997

Background : There are many suggested methods for the indirect determination of anaerobic threshold(AT) using the changes of ventilatory parameters in response to ventilatory load accompanying the increase of blood lactic acid level during exercise and the threshold derived from them is called ventilatory threshold(VT). They include ventilatory equivalent method(VEM), End-tidal $PO_2$ method($PETO_2$). V-slope method(VSM), and respiratory quotient method(RQ). But in the patients with chronic airway obstruction(CAO), the AT determined by ventilatory methods may not reflect true AT because the patients with CAO show inadequate ventilatory response to the increase of blood lactic acid level during excercise. Methods : For the investigation of detection rate and reliability of above four VT determination methods in the patients with CAO, we performed the symptom-limited and maximal incremental exercise test in 17 patients with CAO and 12 normal controls. The incremental workload was 10 W /min in CAO group and 25 W/min in control group. The reliability of VT in each group was investigated by the calculation of Spearman correlation coefficient. Results : The detection rates of VT were 100% by RQ, 91.7% by both VEM and $POETO_2$, and 83.3% by VSM in normal control group, while 94.1% by RQ, 64.7% by VEM and $PETO_2$, and 83.3% by VSM in CAO group. Good correlations were noted among VEM, $POETO_2$, and VSM except RQ in normal control group. But there was no significant correlation except between VEM and $PETO_2$ in CAO group. Conclusions : RQ is very sensitive but crude and VEM is near similar to $PETO_2$. The clinical usefulness of VT determined by ventilatory method might be limited in patients with severe CAO.

• Tuberculosis and Respiratory Diseases
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• v.47 no.4
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• pp.488-497
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• 1999

Background : Identification of the histologic cell type of lung cancer is important because it is related to the treatment modality and prognosis. Currently, many diagnostic methods are used to determine the cell type. We have studied to evaluate the histologic accuracy of each diagnostic methods in lung cancer. Method : 168 cases were analysed retrospectively, who underwent curative thoracotomy for lung cancer in Seoul National University Hospital from January, 1994 to February, 1997. Sputum cytology, percutaneous needle aspiration(PCNA), percutaneous needle biopsy(PCNB), bronchial washing cytology and flexible bronchoscopic biopsy were evaluated respectively. The k coefficient was applied to evaluate the degree of concordance between the histologic diagnosis obtained by each methods and the one derived from thoracotomy. Results : The k value in sputum cytology was 0.86. In the 34 cases with squamous cell carcinoma(SQ), 32 cases were finally diagnosed as having such by thoracotomy. 7 of the 8 cases with adenocarcinoma(AD) turned out to have the same. The k value in PCNA was 0.51. In the 31 cases with SQ, only 14 cases were finally diagnosed as having such. All of the 3 cases with small cell carcinoma(SC) turned out to have the same. The k value in PCNB was 0.77. The diagnosis was correct in 13 of the 16 patients with SQ and in 30 of the 32 cases with AD. The k value in bronchial washing cytology was 1.0. In all of the 29 cases with SQ and all of the 7 cases with AD, the diagnosis was correct. The k value in flexible bronchoscopic biopsy was 0.77. The diagnosis was correct in 51 of the 52 cases with SQ and in 1 of the 2 cases with SC. Conclusion : The concordance rate with the final histologic diagnosis in sputum cytology, PCNB, bronchial washing cytology and flexible bronchoscopic biopsy were excellent ($k{\geq}0.75$), while that in PCNA was fair (k=0.53). Because PCNA showed lower concordance rate than other diagnostic methods, PCNA is recommended to perform with PCNB.

• Journal of Global Scholars of Marketing Science
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• v.18 no.1
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• pp.141-156
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• 2008

Market structure analysis is a very useful tool to analyze the competition boundary of the brand or the company. But most of the studies in market structure analysis, the concern lies in nondurable goods such as candies, soft drink and etc. because of the their availability of the data. In the field of durable goods, the limitation of the data availability and the repurchase time period constrain the study. In the analysis of the automobile market, those of views might be more persuasive. The purpose of this study is to analyze the structure of automobile market based on some idea suggested by prior studies. Usually the buyers of the automobile tend to buy upper tier when they buy in the next time. That kind of behavior make it impossible to analyze the structure of automobile market under the level of automobile model. For that reason I tried to analyze the market structure in the brand or company level. In this study, consideration data was used for market structure analysis. The reasons why we used the consideration data are summarized as following. Firstly, as the repurchase time cycle is too long, brand switching data which is used for the market analysis of nondurable good is not avaliable. Secondly, as we mentioned, the buyers of the automobile tend to buy upper tier when they buy in the next time. We used survey data collected in the U.S.A. market in the year of 2005 through questionaire. The sample size was 8,291. The number of brand analyzed in this study was 9 among 37 which was being sold in U.S.A. market. Their market share was around 50%. The brands considered were BMW, Chevrolet, Chrysler, Dodge, Ford, Honda, Mercedes, and Toyota. �� ratio was derived from frequency of the consideration set. Actually the frequency is different from the brand switch concept. In this study to compute the �� ratio, the frequency of the consideration set was used like a frequency of brand switch for convenience. The study can be divided into 2 steps. The first step is to build hypothetical market structures. The second step is to choose the best structure based on the hypothetical market structures, Usually logit analysis is used for the choice best structure. In this study we built 3 hypothetical market structure. They are type-cost, cost-type, and unstructured. We classified the automobile into 5 types, sedan, SUV(Sport Utility Vehicle), Pickup, Mini Van, and Full-size Van. As for purchasing cost, we classified it 2 groups based on the median value. The median value was $28,800. To decide best structure among them, maximum likelihood test was used. Resulting from market structure analysis, we find that the automobile market of USA is hierarchically structured in the form of 'automobile type - purchasing cost'. That is, result showed that automobile buyers considered function or usage first and purchasing cost next. This study has some limitations in the analysis level and variable selection. First, in this study only type of the automobile and purchasing cost were as attributes considered for purchase. Considering other attributes is very needful. Because of the attributes considered, only 3 hypothetical structure could be analyzed. Second, due to the data, brand level analysis was tried. But model level analysis would be better because automobile buyers consider model not brand. To conduct model level study more cases should be obtained. That is for acquiring the better practical meaning, brand level analysis should be conducted when we consider the actual competition which occurred in the real market. Third, the variable selection for building nested logit model was very limited to some avaliable data. In spite of those limitations, the importance of this study lies in the trial of market structure analysis of durable good.

• Geotechnical Engineering
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• v.2 no.1
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• pp.27-44
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• 1986

The measured soil data are analyzed to the descriptive statistics and classified into the four models of uncorrelated-normal (UNNO), uncorrelated-nonnormal (VNNN), correlatedonnormal(CONN), and correlated-nonnormal(CONN) . This paper presents the comparisons of reliability index and check points using the advanced first-order second-moment method with respect to the four models as well as BASIC Program. A sin91e-mode Performance function is consisted of the basic design variables of bearing capacity and settlements on shallow foundations and input the above analyzed soil informations. The main conclusions obtained in this study are summarized as follows: 1. In the bearing capacity mode, cohesion and bearing-capacity factors by C-U test are accepted for normal and lognormal distribution, respectively, and negatively low correlated to each other. Since the reliability index of the CONN model is the lowest one of the four model, which could be recommended a reliability.based design, whereas the other model might overestimate the geotechnical conditions. 2. In the case of settlements mode, the virgin compression ratio and preccnsolidation pressure are fitted for normal and lognormal distribution, respectively. Constraining settlements to the lower ones computed by deterministic method, The CONN model is the lowest reliability of the four models.

• Korea Journal of Hospital Management
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• v.7 no.1
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• pp.64-87
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• 2002

The purpose of this study is aimed to grasp the factors, which may influence the harmonized organizational efficiency of the objects of hospital structure as well as its structural constituents of each departments of administration, nursing, and para-medical personnels, in order to provide basic data enable to contribute in the development of hospital. The survey data involved in the study was derived from 385 personnels working in 5 medium and small sized hospitals in Seoul area. The main finding of the study can be summarized as follows; 1. The organizational efficiency in accordance with the general characteristics of subjects in order of male, over 30 years of age, university graduates, long-term tenure and high position is higher, whereas, in as much as wage and well trained personnels in administration departments are higher, its organizational efficiency is higher in comparison with those of nursing and para-medical departments. 2. The organizational efficiency in accordance with satisfaction and the motive contributional factors is higher as much as the high satisfactory level in every departments in general. 3. The organizational efficiency in accordance with the factors of job characteristics is higher in as much as difficulty of the jobs is lesser, however there was not statically significance between administration and para-medical departments. In as much as the job circulation is intact, job standard level is higher and the more job responsibility the higher organizational efficiency, while the more workload and the more work feud resulted lower organizational efficiency. It was obvious that the higher professional expertise as well as the training and application level are improving the organizational efficiency. 4. The organizational efficiency in accordance with the factors of structural characteristics was higher in as much as the intercommunication was smooth and the structural formalization level are higher, however there was not statically significance between the participation level of decision making and the organizational efficiency. 5. In as much as higher educational level of over university graduates, management of organization and the job level are satisfied, the psychological motive contributional level is higher, while the lesser job difficulty, the smooth job performance, the higher level of professional expertise, the higher structural formalization level, the smooth intercommunication, have affected as major influence factors of the structural characteristics of organizational efficiency. 6. As the management of hospital organization, the job level and personal relation are satisfied or psychological motive is provided, especially when there are no difficult jobs or smooth job circulation and no job feud are prevailing, it was apparent that the organizational efficiency is improving accordingly. The nursing departments has high educational standard and is satisfied in the management and job level of hospital organization as there are no difficult jobs while the level of hospital's organizational formality is high and the intercommunication is smooth, which are improving the organizational efficiency. The para-medical departments is also satisfied the management and job level of hospital organization and it was apparent that the organizational efficiency is higher in as much as the level of job standardization is high and the intercommunication is smooth. As a result of this study, in order for improving the organizational efficiency of the medium and small sized hospitals, the management and job level as well as personal relation are preferably satisfied, whereas the level of job circulation, job responsibility, the expertise and formalization of organization, intercommunication and etc. should be satisfied, and, therefore, it is advisable to buildup discriminated organizational management and environment for different division on the basis above factors. Since this study is carried on several hospitals in Seoul area, there is a certain limit to generalize its result to all domestic hospitals, nevertheless the gallop poll was made by developing the questionnaires with reasonability and reliability. Especially, as the study was carried by analyzing the comparison of influence factors' difference of organizational efficiency in accordance with the divisional characteristics of the medium and small sized hospitals.

• Journal of Intelligence and Information Systems
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• v.20 no.2
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• pp.59-71
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• 2014

System trading is becoming more popular among Korean traders recently. System traders use automatic order systems based on the system generated buy and sell signals. These signals are generated from the predetermined entry and exit rules that were coded by system traders. Most researches on system trading have focused on designing profitable entry and exit rules using technical indicators. However, market conditions, strategy characteristics, and money management also have influences on the profitability of the system trading. Unexpected price deviations from the predetermined trading rules can incur large losses to system traders. Therefore, most professional traders use strategy portfolios rather than only one strategy. Building a good strategy portfolio is important because trading performance depends on strategy portfolios. Despite of the importance of designing strategy portfolio, rule of thumb methods have been used to select trading strategies. In this study, we propose a SVM-based strategy portfolio management system. SVM were introduced by Vapnik and is known to be effective for data mining area. It can build good portfolios within a very short period of time. Since SVM minimizes structural risks, it is best suitable for the futures trading market in which prices do not move exactly the same as the past. Our system trading strategies include moving-average cross system, MACD cross system, trend-following system, buy dips and sell rallies system, DMI system, Keltner channel system, Bollinger Bands system, and Fibonacci system. These strategies are well known and frequently being used by many professional traders. We program these strategies for generating automated system signals for entry and exit. We propose SVM-based strategies selection system and portfolio construction and order routing system. Strategies selection system is a portfolio training system. It generates training data and makes SVM model using optimal portfolio. We make $m{\times}n$ data matrix by dividing KOSPI 200 index futures data with a same period. Optimal strategy portfolio is derived from analyzing each strategy performance. SVM model is generated based on this data and optimal strategy portfolio. We use 80% of the data for training and the remaining 20% is used for testing the strategy. For training, we select two strategies which show the highest profit in the next day. Selection method 1 selects two strategies and method 2 selects maximum two strategies which show profit more than 0.1 point. We use one-against-all method which has fast processing time. We analyse the daily data of KOSPI 200 index futures contracts from January 1990 to November 2011. Price change rates for 50 days are used as SVM input data. The training period is from January 1990 to March 2007 and the test period is from March 2007 to November 2011. We suggest three benchmark strategies portfolio. BM1 holds two contracts of KOSPI 200 index futures for testing period. BM2 is constructed as two strategies which show the largest cumulative profit during 30 days before testing starts. BM3 has two strategies which show best profits during testing period. Trading cost include brokerage commission cost and slippage cost. The proposed strategy portfolio management system shows profit more than double of the benchmark portfolios. BM1 shows 103.44 point profit, BM2 shows 488.61 point profit, and BM3 shows 502.41 point profit after deducting trading cost. The best benchmark is the portfolio of the two best profit strategies during the test period. The proposed system 1 shows 706.22 point profit and proposed system 2 shows 768.95 point profit after deducting trading cost. The equity curves for the entire period show stable pattern. With higher profit, this suggests a good trading direction for system traders. We can make more stable and more profitable portfolios if we add money management module to the system.

• KSBB Journal
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• v.25 no.6
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• pp.572-576
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• 2010

Biological products, such as live varicella vaccine, are composed of biological substances derived from biological organisms. It is very difficult to identify these biologics' characteristics by analysis of simple physical and chemical methods alone. So the reference material is essential in order to evaluate the quality of bilogics. The 1'st national standard for varicella live vaccine was manufactured, established in 2002 and 2003, and have been used for the manufacturer's quality control and national lot release since then. As the lack of its availability and the decrease of its stability, this study was initiated by National Institute of Food and Drug Safety Evaluation (NiFDS) in 2008 to manufacture and establish the 2nd national standard for varicella live vaccine. The candidate material was manufactured from one of domestic manufacterers and the joint research of the NiFDS and manufacturers of varicella live vaccine was conducted to estimate of the reliable virus content. In the collaborative study, 3 laboratories including NiFDS performed the virus content test more than 7 times and all assay results were statistically analyzed. The mean coefficient of variation (CV) was 1.24%, and the geometric mean titre (GMT) variation range of each laboratory was low. On the basis of the results of this study, the candidate material of 2nd national standard for varicella live vaccine was assigned a potency of 4.26 log10 pfu/0.5 mL, when reconstituted in 0.7 mL.

• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.218-223
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• 2016

The calculation method of ground heat exchange in greenhouses has different ideas in each design standard, so there is a big difference in each method according to the size of greenhouses, it is necessary to establish a more accurate method that can be applied to the domestic. In order to provide basic data for the formulation of the calculation method of greenhouse heating load, we measured the soil temperature distribution and the soil heat flux in three plastic greenhouses of different size and location during the heating period. And then the calculation methods of ground heat exchange in greenhouses were reviewed. The soil temperature distributions measured in the heating greenhouse were compared with the indoor air temperature, the results showed that soil temperatures were higher than room temperature in the central part of greenhouse, and soil temperatures were lower than room temperature in the side edge of greenhouse. Therefore, it is determined that the ground heat gain in the central part of greenhouse and the perimeter heat loss in the side edge of greenhouse are occurred, there is a difference depending on the size of greenhouse. Introducing the concept of heat loss through the perimeter of building and modified to reflect the size of greenhouse, the calculation method of ground heat exchange in greenhouses is considered appropriate. It was confirmed that the floor heat loss measured by using soil heat flux sensors increased linearly in proportion to the temperature difference between indoor and outdoor. We derived the reference temperature difference which change the direction of ground heat flow and the perimeter heat loss factor from the measured heat flux results. In the heating design of domestic greenhouses, reference temperature differences are proposed to apply $12.5{\sim}15^{\circ}C$ in small greenhouses and around $10^{\circ}C$ in large greenhouses. Perimeter heat loss factors are proposed to apply $2.5{\sim}5.0W{\cdot}m^{-1}{\cdot}K^{-1}$ in small greenhouses and $7.5{\sim}10W{\cdot}m^{-1}{\cdot}K^{-1}$ in large greenhouses as design standard data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.239-246
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• 2017

There are various transversal structures (small dams or drop structures) in median and small streams in Korea. Most of them are concrete structures and it is so hard to exclude low-level water. Unless drainage valves and/or gates would not be installed near bottom of bed, sediment from upstream should be deposited and also contaminants attached to the sediments would devastatingly threaten the water quality and ecosystem. One of countermeasures for such problem is the bypass pipe installed underneath the transversal structure. However, there is still issued whether it would be workable if the gravels and/or stones would roll into and be not excluded. Therefore, in this study, the conditions to exclude the rip stone which enter into the bypass pipe was reviewed. Based on sediment transport phenomenon, the behavior of stones was investigated with the concepts from the critical shear stress of sediment and d'Alembert principle. As final results, the basis condition (${\tau}_c{^*}$) was derived using the Lagrangian description since the stones are in the moving state, not in the stationary state. From hydraulic experiments the relative velocity could be obtained. In order to minimize the scale effect, the extra wide channel of 5.0 m wide and 1.0 m high was constructed and the experimental stones were fully spherical ones. Experimental results showed that the ratio of flow velocity to spherical particle velocity was measured between 0.5 and 0.7, and this result was substituted into the suggested equation to identify the critical condition wether the stones were excluded. Regimes about the exclusion of stone in bypass pipe were divided into three types according to particle Reynolds number ($Re_p$) and dimensionless critical shear force (${\tau}_c{^*}$) - exclusion section, probabilistic exclusion section, no exclusion section. Results from this study would be useful and essential information for bypass pipe design in transveral structures.

• Progress in Medical Physics
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• v.25 no.4
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• pp.233-241
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• 2014

The aim of this study is to develop a new software tool for 3D dose verification using $PRESAGE^{REU}$ Gel dosimeter. The tool included following functions: importing 3D doses from treatment planning systems (TPS), importing 3D optical density (OD), converting ODs to doses, 3D registration between two volumetric data by translational and rotational transformations, and evaluation with 3D gamma index. To acquire correlation between ODs and doses, CT images of a $PRESAGE^{REU}$ Gel with cylindrical shape was acquired, and a volumetric modulated arc therapy (VMAT) plan was designed to give radiation doses from 1 Gy to 6 Gy to six disk-shaped virtual targets along z-axis. After the VMAT plan was delivered to the targets, 3D OD data were reconstructed from 512 projection data from $Vista^{TM}$ optical CT scanner (Modus Medical Devices Inc, Canada) per every 2 hours after irradiation. A curve for converting ODs to doses was derived by comparing TPS dose profile to OD profile along z-axis, and the 3D OD data were converted to the absorbed doses using the curve. Supra-linearity was observed between doses and ODs, and the ODs were decayed about 60% per 24 hours depending on their magnitudes. Measured doses from the $PRESAGE^{REU}$ Gel were well agreed with the TPS doses at central region, but large under-doses were observed at peripheral region at the cylindrical geometry. Gamma passing rate for 3D doses was 70.36% under the gamma criteria of 3% of dose difference and 3 mm of distance to agreement. The low passing rate was resulted from the mismatching of the refractive index between the PRESAGE gel and oil bath in the optical CT scanner. In conclusion, the developed software was useful for 3D dose verification from PRESAGE gel dosimetry, but further improvement of the Gel dosimetry system were required.