• Journal of Ocean Engineering and Technology
• /
• v.31 no.5
• /
• pp.340-345
• /
• 2017

It is important to predict the hydrodynamic maneuvering derivatives, which consist of the forces and moment acting on a hull during a maneuvering motion, when estimating the maneuverability of a ship. The estimation of the maneuverability of a ship with a change in the stern hull form is often performed at the initial design stage. In this situation, a method that can reflect the change in the hull form is necessary in the prediction of the maneuverability of the ship. In particular, the linear hydrodynamics maneuvering derivatives affect the yaw checking motion as the key factors. In the present study, static drift calculations were performed using Computational Fluid Dynamics (CFD) based on Reynolds Average Navier-Stokes (RANS) for a 40-segment hull. A prediction method for the linear hydrodynamic maneuvering derivatives was proposed using the slender body theory from the distribution of the lateral force acting on each segment of the hull. Moreover, the results of a comparison study to the model experiment for KVLCC1 performed by KRISO are presented in order to verify the accuracy of the static drift calculation. Finally, the linear hydrodynamic maneuvering derivatives obtained from both the model test and calculation are compared and presented to verity the usefulness of the method proposed in this study.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.1
• /
• pp.66-73
• /
• 2010

This work was focused on the material parameter extraction for the isothermal cyclic deformation analysis for which Chaboche(Combined Nonlinear Isotropic and Kinematic Hardening) and Overlay(Multi Linear Hardening) models are normally used. In this study all the parameters were driven especially based on Overlay theories. A simple method is suggested to find out best material parameters for the cyclic deformation analysis prior to the isothermal LCF(Low Cycle Fatigue) analysis. The parameter extraction was done using 400 series stainless steel data which were published in the reference papers. For simple and quick review of the parameters extracted by suggested method, 1D FORTRAN program was developed, and this program could reduce the time for checking the material data tremendously. For the application to FE code ABAQUS user subroutine for the material models was developed by means of UMAT(User Material Subroutine), and the stabilized hysteresis loops obtained by the numerical analysis were in good harmony with test results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.12
• /
• pp.852-858
• /
• 2010

In an absorption chiller, solution is circulated by a solution pump with an inverter to vary flow rate depending on operating conditions. For optimal operation, the solution level in the high temperature generator should be kept constant. However, a sensor for measuring continuous level is not available because of varying solution concentration. Instead, level switches are used and hence feedforward control associated with limit checking is a common practice. In the study, inverter frequencies are estimated from a dynamic simulation model and pump performance. Designed frequencies are compared with those implemented in real chillers. It was found that the frequencies used in real chillers are larger than those needed in circulation flow rates. It was intended to prevent system shut-off caused by dry-out. However, it is necessary to minimize the excessive frequency setting in order to reduce frequent pump stops and the range of solution level for continuous pump operation.

• Earthquakes and Structures
• /
• v.19 no.2
• /
• pp.119-128
• /
• 2020

In seismic design of a pylon supporting transmission lines in an overhead electricity transmission system, an estimation of the fundamental periods of the pylon in two orthogonal vertical planes is necessary to compute the seismic forces required for sizing pylon members and checking pylon deflections. In current practice, the fundamental periods of a pylon in two orthogonal vertical planes are typically obtained from eigenvalue analyses of a model consisting of the pylon of interest as well as some adjacent pylons and the transmission lines supported by these pylons. Such an approach is onerous and numerically inconvenient. This research focused on development of a simplified method to determine the fundamental periods of pylons. The simplified method is rooted in Rayleigh's quotient and is based on a single-pylon model. The force vectors that can be used to generate the shape vectors required in Rayleigh's quotient are presented in detail. Taking three pylons selected from representative overhead electricity transmission systems having different design parameters as examples, the fundamental periods of the chosen pylons predicted from the simplified method were compared with those from the rigorous eigenvalue analyses. Result comparisons show that the simplified method provides reasonable predictions and it can be used as a convenient surrogate for the tedious approach currently adopted.

• Korean Security Journal
• /
• no.8
• /
• pp.281-308
• /
• 2004

With regard to problems related to qualification of Private Security, this study is qualitatively to develop education & training program from the viewpoint of education for the purpose of checking professionalism of Security guard. Offering the solutions for improvement by analyzing problems of articles related to training for Private Security guard prescribed in existing 'Law of Guarding', I made studies of development of practical affairs-centered education & training program for Private Security guard on the basis of Private Security guard' duties. Education & training program for Private Security guard must be made up of practical affairs-centered one related to concrete duties. Also because it needs to be made on the basis of a model planned for the program with combined method, this study gave example of model and contests of education & training program based on duties of Facilities Security. Main duties of cPrivate Security guard can be divided into four duties; duties on their own posts, patrolling, control of going in and out, dealing with accidents and so on. Private Security guard are given main duties by each post, and after adjusting conditions according to personnel organization, they perform their own duties. As education & training program based on Private Security guard' duties, common education & training program for the new-appointed, practical affairs-centered education & training program, education & training program for superintendents, service education & training program and so on are provided.

• Proceedings of the Korea Society for Simulation Conference
• /
• 2002.05a
• /
• pp.61-65
• /
• 2002

These days, in order to satisfy the complex and various demands of the customers, the telecommunication networks must provide rapid and flexible services, with the support of efficient service and network management systems. To satisfy these requirements, many objects for management have been released to manage network services and elements. But there are no efficient ways to manage these newly managed objects in object-oriented software. Therefore, we study several problems, when a subsystem using object-oriented technique is implemented. The first problem is that interface works between realized application programs using its technique. The second problem is that reusability of internal managed objects is difficult. In this paper, we will point out some problems and to solve these problems, we have proposed the Object Management System (OMS) architecture, which supports a transparent interface between object-oriented applications and the distributed data repositories. Also in order to manage efficient business objects stored in the different repositories, we suggest a method for integrating dynamic information resources in heterogeneous and distributed network environments. Finally, we applied OMS to TINA(Telecommunication Information Network Architecture) domain, implemented OMS, and verified it with SMV(Symbolic Model Verifier) which is model checking technology.

• Journal of Society of Preventive Korean Medicine
• /
• v.15 no.3
• /
• pp.101-114
• /
• 2011

The purpose of this study was to analyze of Hospital Coordinator based on the DACUM(Developing A Curriculum) method. The contents of this study were to extract the duties, tasks consisting of job of Hospital Coordinator and to investigate levels of importance, difficulty, frequency and entry level on each task, and to make out a job model of Hospital coordinator. A DACUM committee was composed to analyze job of Hospital Coordinator and the committee members were total 17, a facilitator, 15 hospital administrator and a recorder. The major findings of this study were as the followings ; first, duties in job of Hospital Coordinator were total 10, which were organization of Hospital Coordinator affairs, customerfacing services, consultation support, customer counsel, customer management, financial management, medical service planning, medical service marketing, organizational management, image making management, and self-development. And total tasks in job of Hospital coordinator were 76. Second, the tasks which were important, difficult, frequent and essential in entry step of occupation were counseling before consultation, explaining treatment plan after consultation, checking progress of consultation, answering teleconsultation, and finding out customer's consultation information. Third, a job model of Hospital Coordinator was constructed based on the results of DACUM job analysis.

• Journal of Environmental Health Sciences
• /
• v.7 no.2
• /
• pp.97-105
• /
• 1981

Water Pollution of Gwangju Stream was examined for four months from 22 March 1981 to 7 June, 1981. For checking the water pollution, 6 sampling positions were selected 5 from main stream. We assumed that the water pollution of Gwangju stream was due to the organic materials, which came from the domestic sewage. The apparatus for this test were pH meter (Orion model 301), Dissolved Oxygen & Temperature meter(Delta model 1010). The results we obtained are as follows: 1. The average range for mid-stream(sp. 3, 4) was 3. 10~2.73ppm of Dissolved Oxygen(DO), 80.23~102.95ppm of Biochemical Oxygen Demand (BOD), 195. 10~165.90ppm of Suspended Solid (SS), 6.6~6.7 of pH. 2. The plankton identification in this survey period showed Cyanophyceae is 4 genera 5 species, Bacillariophycea 11 genera 14 species, Chlorophyceae 8 genera 15 species and Zooplankton 6 genera 7 species: total 29 genera 41 species. 3. To appear dominant plankton in polluted water, there were Paramecium, Euglena and Oscillatoria. 4. The results of biological water analysis were as follows: st. 1 was B-mesosaprobic to oligosaprobic, but st. 4 and st. 5 at stream in the midtown area seemed to be polysaprobic.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.11
• /
• pp.421-428
• /
• 2020

The study investigates the causal factors affecting mobile banking services acceptance by customers in Thailand. This study employs quantitative research methodology and non-probability sampling to draw 400 mobile banking users from the population who are the mobile banking users of commercial banks in Thailand. The online questionnaires were used as a research tool to collect data with the Cronbach's alpha coefficient as 0.931. By using the structural equation model to analyze data, the results have shown that service quality, perceived usefulness, perceived ease-of-use, safety in use, and social factors influenced mobile banking services acceptance by customers in Thailand.By checking the harmony with the statistics χ² = 108.618, df. = 86, χ²/df. = 1.263, p-value = .050, CMIN/DF =1.263, GFI = .989, AGFI=.962, TLI= .962, CFI = .976, RMSEA = .037,along with testing the weight factor. In conclusion, the research model was found to be harmonious with the empirical data at the significance level 0.05. The findings of this study suggest that the commercial banks should apply this research to understand the acceptance behavior of mobile banking users, also to determining marketing strategies, identifying opportunities and creating a competitive advantage for their services in the future.

• Journal of Information Processing Systems
• /
• v.10 no.4
• /
• pp.503-522
• /
• 2014

In the cursive handwriting recognition process, script trajectory segmentation and modeling represent an important task for large or open lexicon context that becomes more complicated in multi-writer applications. In this paper, we will present a developed system of Arabic online handwriting modeling based on graphemes segmentation and the extraction of its geometric features. The main contribution consists of adapting the Fourier descriptors to model the open trajectory of the segmented graphemes. To segment the trajectory of the handwriting, the system proceeds by first detecting its baseline by checking combined geometric and logic conditions. Then, the detected baseline is used as a topologic reference for the extraction of particular points that delimit the graphemes' trajectories. Each segmented grapheme is then represented by a set of relevant geometric features that include the vector of the Fourier descriptors for trajectory shape modeling, normalized metric parameters that model the grapheme dimensions, its position in respect to the baseline, and codes for the description of its associated diacritics.