• Journal of Ocean Engineering and Technology
• /
• v.11 no.4
• /
• pp.213-220
• /
• 1997

In this study, a design for a shape of centrifugal pump impeller has been performed using a p.c. under a Windows environment. Interaction between a user and a computer has been easily established using the Visual Basic. In determining an outer diameter of an impeller, steps are divided into two, a basic computational step and a refinment step. In this way user can enter his/her experience at the refinment step and hence can expect to lessen the nonlinear nature inherent to the design. In determining a shape of a side view of an impeller, the Bezier cubic curve has been used, and it can be seen that the Bezier cubic curves are well suited in the shape design under a Windows environment. By simply manipulating the four control points, one can generate various cubic curves among which one is selected. Also, a simple method, which can determine the curved position of an impeller vane, has been developed. These data can be used for final CAD drawings.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.24 no.7
• /
• pp.1073-1080
• /
• 2000

Moisture transfer property of fabrics has known as one of the most important factors deciding wearer's subjective comfort not only thermally but also of sensorial. As a decisive property of fabric materials in determining human sensorial comfort, moisture vapor management property of heat resistant workwear material was examined in terms of increasing and decreasing rate and maximum value of relative humidity in the microclimate under the sweat pulse situation. An unique moisture regulation index, B$_{d}$, was calculated from the measurements using a novel dynamic sweating hot plate apparatus and was used to assess the buffering capacity of fabrics against a moisture vapor sweat pulse.e.

• Speech Sciences
• /
• v.15 no.4
• /
• pp.67-81
• /
• 2008

The accuracy rate of P2G (Phoneme-to-Grapheme) is one of the important factors determining the quality of unlimited voice recognition (VR) systems. Few studies were, however, conducted to reduce ambiguities of a phoneme string which can be segmented into a variety of different linguistic units (i.e. morphemes, words, eo-jeols), thus be transformed into more than one grapheme string. This paper is a preliminary research for building a large knowledge base of those homonymic & heterographic units(HHUs), which will provide unlimited Korean VR systems with more accurate P2G information. This paper analyzes 2 main factors generating HHUs: (1) boundary determination of the prosodic unit; (2) its segmentation into linguistic units. In this paper, linguistic characteristics determining variable boundaries of a prosodic unit are investigated, and the ambiguity types of HHUs are classified in accordance with their morphological and syntactic structures as well as with the phonological rules governing them.

• Korea-Australia Rheology Journal
• /
• v.20 no.1
• /
• pp.35-42
• /
• 2008

An inverse ferrofluid composed of micron sized polymethylmethacrylate particles dispersed in ferrofluid was used to investigate the effects of test duration times on determining the flow curves of these materials under constant magnetic field. The results showed that flow curves determined using low duration times were most likely not measuring the steady state rheological response. However, at longer duration times, which are expected to correspond more to steady state behaviour, we noticed the occurrence of plateau and decreasing flow curves in the shear rate range of $0.004\;s^{-1}$ to ${\sim}20\;s^{-1}$, which suggest the presence of nonhomogeneities and shear localization in the material. This behaviour was also reflected in the steady state results from shear start up tests performed over the same range of shear rates. The results indicate that care is required when interpreting flow curves obtained for inverse ferrofluids.

• Korean System Dynamics Review
• /
• v.11 no.3
• /
• pp.61-86
• /
• 2010

This research analyzed on the future energy society of Korea in 2030 using system thinking approach. Key uncertainty factors determining the future energy society were analyzed in a multi disciplinary view point such as politics, economy, society, ecology and technology. Three causal loop diagrams for the future energy system in Korea and related policy leverages were shown as well. 'Global economic trends', 'change of industrial structure' and 'energy price' were identified as key uncertainty factors determining the Korean energy future. Three causal loop diagrams named as 'rate of energy self－sufficiency and alternative energy production', 'economic activity and energy demand' and 'Excavation of new growth engines' were developed. We integrated those causal loop diagrams into one to understand the entire energy system of the future, proposed three strategic scenarios(optimistic, pessimistic and most likely) and discussed implications and limits of this research.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.30 no.3
• /
• pp.117-126
• /
• 2007

It has been a major issue to repair the broken system quickly for improvement of productivity and utilization. Generally, high utilization of system requires the high amount of spare parts in inventory and inventory cost. Therefore, it is necessary to determine the proper amount of inventory with regard to utilization of system. This study designs a methodology for determining the proper amount of inventory level in a two-echelon spare parts distribution system. The requirements are to satisfy proper customer demands at a distribution center and to maintain over the utilization of the whole system at customers. This methodology minimizes total inventory investment at a distribution center and customers.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.10
• /
• pp.1911-1915
• /
• 2009

The problem of determining the proper capacity of electric vehicle charging station is studied in the presented paper. Based on the expected arrival rate and the expected charging time, we calculate the proper capacity that guarantees electric vehicles get service better than a given lower bound which is termed the loss of charging probability. The problem is studied by using certain queueing models. We first formulate the problem as a queueless model of type M/M/n/n, known as the Erlang loss system. And then the M/M/n/K type queueing model is formulated to consider the parking space constraint. Results of the study may be used for designing the electric vehicle charging station.

• KIEE International Transactions on Power Engineering
• /
• v.5A no.3
• /
• pp.280-285
• /
• 2005

This paper proposes a novel method for determining the kind and rating of power quality solutions. To determine the kind of solution, event cause and direction are utilized. According to the event cause and direction, an adequate type of solution is determined for effective compensation. To rate the required capacity of solution, the concept of lost energy is adopted. Lost voltage, lost power and lost energy are calculated and the rating of the solution is determined to compensate a specific event. The rating method that utilizes the result of stochastic diagnosis is also proposed. A power quality index such as CP95 is adopted for solution suggestion. The method developed in this paper is applied to the test system and proved to be useful for enhancing the power quality of the customer system. It can provide customers with information pertaining to what is a proper and cost-effective solution among various compensating devices.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.185.2-185.2
• /
• 2003

The typical approach of virtual screening is to prepare a 3D database and dock each member to the receptor, and carry out a post-analysis to make a final selection of compounds to be tested. The biological test of these compounds leads to 'hit'. The size of the 3D database is rate-determining factor because the docking process is still time-consuming method. The number of compounds for biological testing is cost-determining factor because the materials used in the test are cost-consuming. The use of the representative subsets derived from the entire database help reduce runtime of docking procedure. (omitted)

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.6 no.3
• /
• pp.175-181
• /
• 1994

This paper deals with the correlation of absorption rate in absorber and evaporation rate in evaporator. The evaporator consists of a copper tube of 10mm dia, and 600mm long and chilled water flowing through the tube is fed by the chilled water circulator. The flowrate of LiBr-water solution in the absorber plays a significant role in determining the magnitude of the heat transfer rate from chilled water to refrigerant There exists a flowrate of solution which has a maximum value of heat transfer. It is interesting to note that the absorption rate of absorber increases with increasing the heat transfer rate of the evaporator. Also, absorption rate increases with evaportation rate, and the ratio(the former/the other) depends on the inlet temperature of LiBr-water solution in the absorber. The heating capacity in the absorber is higher than the refrigerating capacity in the evaporator.