• The Korean Journal of Health Service Management
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• 제6권1호
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• pp.117-128
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• 2012

This study purports to investigate the difference between upward and downward feedback and to find out the strategy to enhance the validity and reliability of the multi-source feedback system. Data were collected from 88 middle-level managers working at divisions of nursing, administration, and clinical technology at a university hospital located in north-eastern part of South Korea. Data about multi-source feedback of the year 2008 and 2009 were obtained from the department of personnel management under the permission of hospital top management. The collected data were analyzed using t-test, and correlation analysis. The major findings of the study were as follows: First, the scores of downward feedback were always higher than those of the upward feedback. Second, the scores of downward feedback were always higher than those of the upward feedback in both nursing and administrative staff, while no significant difference was found in technological staff. Third, the upward and downward feedback scores were significantly different in terms of the evaluation factors. Fourth, there were significant correlations between total scores of downward and upward feedback, and evaluation factor scores. In conclusion, the composition and weight of measurement items of multi-source feedback needs to be designed differently in terms of each job characteristics.

• Journal of Korea Water Resources Association
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• 제38권5호
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• pp.333-343
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• 2005

The upwind model is well known to simulate shockwaves, but it is rarely applied to natural rivers because of problems caused by the source terms. Although several methods have been developed to deal with the source terms, none of them has been applied to natural rivers. This paper deals with application of the upwind model to the natural river. An implicit upwind model is applied to a hypothetical irregular channel and a natural river with highly irregular bed, width, and hydraulic structures. Different types of the flows including steady-state flow, flood wave, dam-break wave, and bore are simulated to test accuracy and applicability of the implicit upwind model. It is proved that the model can simulate various types of flows in natural rivers with high accuracy and robustness.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2338-2356
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• 2019

Vehicular ad-hoc network (VANET) is the name of technology, which uses 'mobile internet' to facilitate communication between vehicles. The aim is to ensure road safety and achieve secure communication. Therefore, the reliability of this type of networks is a serious concern. The reliability of VANET is dependent upon proper communication between vehicles within a given amount of time. Therefore a new formula is introduced, the terms of the new formula correspond 1 by 1 to a class special ST route (SRORT). The new formula terms are much lesser than the Inclusion-Exclusion principle. An algorithm for the Source-to-Terminal reliability was presented, the algorithm produced Source-to-Terminal reliability or computed a Source-to-Terminal reliability expression by calculating a class of special networks of the given network. Since the architecture of this class of networks which need to be computed was comparatively trivial, the performance of the new algorithm was superior to the Inclusion-Exclusion principle. Also, we introduce a mobility metric called universal speed factor (USF) which is the extension of the existing speed factor, that suppose same speed of all vehicles at every time. The USF describes an exact relation between the relative speed of consecutive vehicles and the headway distance. The connectivity of vehicles in different mobile situations is analyzed using USF i.e., slow mobility connectivity, static connectivity, and high mobility connectivity. It is observed that $p_c$ probability of connectivity is directly proportional to the mean speed ${\mu}_{\nu}$ till specified threshold ${\mu}_{\tau}$, and decreases after ${\mu}_{\tau}$. Finally, the congested network is connected strongly as compared to the sparse network as shown in the simulation results.

• Journal of the Korean Society for Library and Information Science
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• 제47권3호
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• pp.275-293
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• 2013

This study conducted comparative analysis of cataloging descriptions and rules in KCR 4 and CCR 2, as follows, for the purpose of seeking understanding of classical materials cataloging rules and networking of oriental historical data cataloging (bibliographical descriptions). First, to compare the general rules, the objects of descriptions and composition of descriptions, recording order, and punctuation and information source of descriptions were analyzed. As a result, KCR 4 is more detailed in terms of author role identifications and information source regulations and CCR2 is more detailed in terms of regulations related to printing and publications and serial publications. Second, to compare the details, the main titles and liability indications, edition details, publication details and format details, and note details. As a result, regarding the description of edition type and publication details, KCR4 has detailed regulations and CCR2 has characteristic summary in terms of note details.

• Journal of Korea Water Resources Association
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• 제44권3호
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• pp.249-262
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• 2011

In this study, in order to reduce the numerical oscillation due to the unbalance between source and flux terms as the HLLC scheme is applied to the flow analysis on the irregular bed topography, a unstructured finite volume model based on the well-balanced HLLC scheme and the shallow water equations is developed and applied to problems of dam-break waves. The well-balanced HLLC scheme considers directly the gradient of bed topography as the flux terms is calculated. This scheme provides the good numerical balance between the source and flux terms in the case of the application to the steady-state transcritical flow. To verify the numerical model developed in this study, it is applied to three cases of hydraulic model experiments and a field case study of Mapasset dam failure (France). As a result of the verification, the predicted numerical results agree relatively well with available laboratory and field measurements. The model provides slightly more accurate results compared with the existing models.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제33권7호
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• pp.18-25
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• 2005

In this study, the main focus is the simulation of acoustic wave scattering in trailing edge and the analysis of the generation mechanism of instability wave by the interaction of trailing edge, shear flow and initial disturbance. The numerical algorithm is based on CFD/CAA hybrid method with high-order computational aeroacoustic method. It is found that steady mean flow gradient terms play a crucial role on the generation of instability wave through the comparison of simulations of Simple Linearized Euler Equation and Full Linearized Euler Equation. Through the comparison with the results of Full Navier-Stokes Equation, it is reasonable and efficient to use the Full Linearized Euler Equation in the initial generation mechanism of the instability wave near the trailing edge.

• Journal of Korean Society for Atmospheric Environment
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• 제14권1호
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• pp.11-23
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• 1998

The purpose of this study was to survey chemical distribution of inorganic elements and ions in the submicron particles, to characterize qualitatively emitting sources by factor analysis, and finally to reveal existing patterns in terms of chemical compounds by a stepwise multiple regression analysis. Total of 141 samples were collected by a cascade impactor from 1989 to1996. Fifteen chemical species (Al, Ba, Cd, K, Pb, Cu, Fe, Ni, $Cl^-, NO_3^-, SO_4^{2-}, K^+, Mg^{2+}, Ca^{2+}, and Na^+$) were characterized by AAS and IC. The study showed that average seasonal levels of submicron particulate matters $(d_p<0.43 \mum)$ were 18.7 $\mug/m^3$ in spring, 15.5 $\mug/m^3$ in summer, 15.7 $\mug/m^3$ in fall, and 24.5 $\mug/m^3$ in winter, respectively. All of the anion concentrations in the particle were highest in the winter season. By applying a factor analysis, 5 source patterns were qualitatively obtained, such as sulfate related source, nitrate related source, oil burning source, calcium related source, and coal combustion source. Finally, when applying a stepwise multiple regression analysis, the results clearly showed that $Na^+ and Ca^{2+}, K^+ and Ca^{2+}, NO_3^-$ and relative humidity, $Cl^-$ and ambient temperature, $Ca^{2+} and Cl^-, Mg^{2+} and SO_4^{2-}, Na^+ and NO_3^-, and Ca^{2+} and NO_3^-$, respectively, are negatively contributed to each other. As a result of those statistical analysis, we could suggest that some chemical compounds in the submicron particles such as$NaNO_3, MgSO_4, Ca(NO_3)_2, and CaCl_2$ may not exist on the filter as final composing products; however, other compounds may possibly exist in the form of $Mg(NO_3)_2, CaSO_4, Na_2SO_4, K_2SO_4, MgCl_2, NaCl, and KCl$. Thus, it must be necessary to identify differences between the results of above statistical analysis and of the real world by laboratory experiments.

• Transactions on Electrical and Electronic Materials
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• 제17권2호
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• pp.57-68
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• 2016

In this study, we present the modern hybrid system based power generation for electric vehicle applications. We describe the hybrid structure of modified current source based DC - DC converters used to extract the maximum power from Photovoltaic (PV) and Fuel Cell system. Due to reduced dc-link capacitor requirement and higher reliability, the current source inverters (CSI) better compared to the voltage source based inverter. The novel control strategy includes Distributed Maximum Power Point Tracking (DMPPT) for photovoltaic (PV) and fuel cell power generation system. The proposed DC - DC converters have been analyzed in both buck and boost mode of operation under duty cycle 0.5>d, 0.5<d<1 and 0.5<d for capable electric vehicle applications. The proposed topology benefits include one common DC-AC inverter that interposes the generated power to supply the charge for the sharing of load in a system of hybrid supply with photovoltaic panels and fuel cell PEM. An improved control of Direct Torque and Flux Control (DTFC) based induction motor fed by current source converters for electric vehicle.In order to achieve better performance in terms of speed, power and miles per gallon for the expert, to accepting high regenerative braking current as well as persistent high dynamics driving performance is required. A simulation model for the hybrid power generation system based electric vehicle has been developed by using MATLAB/Simulink. The Direct Torque and Flux Control (DTFC) is planned using Xilinx ISE software tool in addition to a Modelsim 6.3 software tool that is used for simulation purposes. The FPGA based pulse generation is used to control the induction motor for electric vehicle applications. FPGA has been implemented, in order to verify the minimal error between the simulation results of MATLAB/Simulink and experimental results.

• Journal of Preventive Medicine and Public Health
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• 제38권4호
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• pp.420-424
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• 2005

Objectives : A few culture-confirmed cases of S. sonnei have been notified from Korean hospitals. The source of epidemic can't be firmly determined in such cases because of the rarity of this illness in the local communities and the timing of the outbreaks. The objective of this study is to estimate the source of epidemic by investigating the patients' lifestyles. Methods : Alibi verification was used to access the presumed source of the epidemic. PCR (Polymerase Chain Reaction) was used to rapidly detect the genes of Shigella in water specimens. Results : The common lifestyle trait among the Shigella infected patients was connected with Mt. Martyr in J city, Korea. The first patient's son had gone on a pilgrimage to Mt. Martyr with 41 friends and he had only eaten rice cakes on April 5th; the second patients had visited Mt. Martyr with their mother for a picnic on April 12th; the third patient had visited Mt. Martyr with 22 friends for a pilgrimage and the patient had only drunk holy water on April 13th. Therefore, the holy water of Mt. Martyr was reckoned to be the source of the epidemic. PCR detected the genes of Shigella two days before the S. sonnei was confirmed. Conclusion : The patients' lifestyles for 7 days before the onset of symptoms should be determined in terms of time, place and contacted people to find the source of infection when cases with food poisoning are seen in the hospital setting.

• Journal of KIISE:Software and Applications
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• 제30권1_2호
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• pp.19-30
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• 2003

Based upon XML, a standard document format on the web, there have been many active studies on e-Commerce, wireless communication, multimedia technology and so forth. JML is an XML application suitable for understanding and reusing the source code written using JAVA for various purposes. And it is a DTD which can effectively express various information related to hierarchical class structures, class/method relationships and so on. This paper describes a tool which generates JML document by extracting a comment information from Java source code and information helpful for reusing and understanding by JML in terms of the reverse engineering and a tool which generates a skeleton code of Java application program from the document information included in the automatically or manually generated JML document in terms of the forward engineering. By using the result of this study, the information useful and necessary for understanding, analyzing or maintaining the source code can be easily acquired and the document of XML format makes it easy for developers and team members to share and to modify the information among them. And also, the Java skeleton coed generated form JML documents is a reliable robust code, which helps for developing a complete source code and reduces the cost and time of a project.