• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.18 no.1
• /
• pp.59-67
• /
• 2009

The purpose of this study is to provide a decision support to select an appropriate layered manufacturing(LM) machine that suits the application of a part. Selection factors include concept model, form/fit/functional model, pattern model far molding, material property, build time and part cost that greatly affect the performance of LM machines. However, the selection of a LM is not an easy decision because they are uncertain and vague. For this reason, the aim of this research is to propose hybrid multiple attribute decision making approaches to effectively evaluate LM machines. In addition, because subjective considerations are relevant to selection decision, a fuzzy logic approach is adopted. The proposed selection procedure consists of several steps. First, we identify LM machines that the users consider After constructing the evaluation criteria, we calculate the weights of the criteria by applying the fuzzy Analytic Hierarchy Process(AHP) method. Finally, we construct the fuzzy Technique of Order Preference by Similarity to Ideal Solution(TOPSIS) method to achieve the ranking order of all machines providing the decision information for the selection of LM machines.

• Structural Engineering and Mechanics
• /
• v.20 no.6
• /
• pp.631-653
• /
• 2005

In this work, the mechanism of damping and its theoretical evaluation for layered aluminium cantilever structures jointed with a number of equispaced connecting bolts under an equal tightening torque have been considered. Extensive experiments have been conducted on a number of specimens for comparison with numerical results. Intensity of interface pressure, its distribution pattern, dynamic slip ratio and kinematic coefficient of friction at the interfaces, relative spacing of the connecting bolts, frequency and amplitude of excitation are found to play a major role on the damping capacity of such structures. It is established that the damping capacity of structures jointed with connecting bolts can be improved largely with an increase in number of layers maintaining uniform intensity of pressure distribution at the interfaces. Thus the above principle can be utilized in practice for construction of aircraft and aerospace structures effectively in order to improve their damping capacity which is one of the prime considerations for their design.

• Journal of Plant Biology
• /
• v.34 no.2
• /
• pp.107-112
• /
• 1991

The atrichomatous wall of ovary in Calotropis procera becomes highly pubescent in the young fruit, but scabrous I the mature fruit. The single layered epicarp develops from the outer epidermis of the ovary wall. The mesocarp which develops from the mesodermis is distinguished into outer, middle and inner zones. The central mesocarp breaks up in the course of fruit development and disintegrate to form large air chambers. The 2-3 layered lignified endocarp develops from the inner epidermis as well as from the inner mesodermis layers of the ground tissue and shows a‘parquetry pattern’of cell arrangement in surface view. The parenchymatous becomes aerenchymatous in the mature fruit. Fruit dehiscence in marginicidal (ventricidal).

• Journal of the korean society of oceanography
• /
• v.32 no.1
• /
• pp.8-16
• /
• 1997

The ventilation theory developed by Luyten, Pedlosky and Stommel (1983) is applied to the East Sea to understand the general circulation pattern of the Intermediate Water, especially the ventilated circulation beneath the Tsushima Warm Current. The original model is slightly modified such that it takes the inflow-outflow of the Tsushima Current into consideration. Results of the model indicate that for sufficiently strong Ekman pumping, the Intermediate Water circulates cyclonically by ventilation. The Intermediate Water subducts beneath the Tsushima Warm Water through the western boundary layer. Off the western boundary layer, it turns northward, outcrops to the north by passing the polar front and continues to flow northward until it finally is absorbed by the northern boundary layer. This result seems to be compatible with some recent observations. Over the ventilated area, the transport of the Tsushima Current is negligible and most transport occurs in the shadow area where the Intermediate layer is motionless indicating that, over the deep motionless layer, the two-layered vertical structure under consideration becomes substantially single-layered.

• Journal of Ocean Engineering and Technology
• /
• v.8 no.1
• /
• pp.105-113
• /
• 1994

Double-diffusive convection induced by simultaneously-imposed lateral temperature and concentration gradients in a rectangular enclosure with aspect retio, 2.0 has been studied experimentally for adiabatic and isothermal horizontal boundary conditions. Visual observations show two distinct flow structures depending on the buoyancy ratio. The unicell flow structure is observed for a lower buoyancy ratio while the layered flow structure appears for a higher buoyancy ratio. There exists an unstable flow regime between two buoyancy ratios.

• Journal of the Semiconductor & Display Technology
• /
• v.11 no.3
• /
• pp.7-11
• /
• 2012

Among various wet cleaning methods, megasonic and jet spray gained their popularity in single wafer cleaning process for the efficient removal of particulate contaminants from the wafer surface. In the present study, we evaluated these two cleaning methods for particle removal efficiency (PRE) and pattern damage on the aluminum layered wafer surface. Also the effect of $CO_2$ dissolved water in jet spray cleaning is assessed by measuring PRE. It is observed that the jet spray cleaning process is more effective in terms of PRE and pattern damage compared to megasonic cleaning and the mixing of $CO_2$ in the water during jet sprays further increases the PRE. We believe that the outcome of the present study is useful for the semiconductor cleaning process engineers and researchers.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7549-7554
• /
• 2015

The aim of this study was to develop gastric retentive bi-layered tablet using floating drug delivery technique. Metformin was selected as a model drug due to its narrow absorption window as well as very highly water solubility. These properties of metformin led to be difficult controlling the drug release. The bi-layered tablet was prepared with bi-layered compression machine to minimize interference between floating part and controlling part. The tablet weight, appearance and hardness were evaluated after compression process. The times of 'time to floating' and 'Floating duration' were tested for floating ability and drug release study was also carried out to understand drug release behavior. Furthermore, the drug release of bi-layered tablet was compared with marketed metformin tablet with sustained release pattern (Glucopharge XR$^{(R)}$).The floating ability and drug release behaviors were well controlled by changing amounts of $NaHCO_3$ (floating substance) and hydroxypropyl methylcellulose (HPMC; release control material). Bi-layered tablet had 13s of time to float, over 10h of floating duration and very similar drug release behavior compared with Glucopharge XR$^{(R)}$($f_2$: 89.6). Consequently, the bi-layered tablet with floating ability was successfully prepared and these properties can maximize the efficacy of metformin.

• Korean Journal of Human Ecology
• /
• v.23 no.4
• /
• pp.665-680
• /
• 2014

The purpose of this study was to develop the construction process of orthopedic compression garments (OCG) for balancing of the left and right lumbar muscle power and strength to prevent low back pain. One male subject having low back pain was involved for investigating of the lumbar muscle power. EMG (Telemyo DTS2, Noraxon, U.S.A) was measured with/ without 3 types of waist assistant belt around the waist area of the subject. Based on the electromyogram value of left and right body, OCG were constructed as follows. Firstly, stretchable t-shirts type with supportive waist belt was selected for the convenience of wearing and laundering the OCG. The design lines of the front and back waist parts were created depending on the anatomy of the torso. Secondly, 3D pattern was developed using 3D Clo, RapidForm XOR, 2C-AN, and Yuka CAD program to increase the fit of the OCG. Finally, stretchable power-net was layered as linings in two ways, a single lining and double layered linings, and evaluated measuring lumbar muscle EMG by five subjects with low back pain. As the results, they were effective to balance the left and right lumbar muscle power and strength. Also the OCG with the double layered power-net lining was superior to the one layered lining in terms of fit and comfort.

• Journal of Forest and Environmental Science
• /
• v.28 no.1
• /
• pp.56-62
• /
• 2012

There is little information about appropriate greenspace structures to satisfy aesthetic function in Korea. The purpose of this study was to analyze Korean's aesthetic preferences for greenspace structures concerned with urban tree plantings of an areal type to explore desirable greenspace landscapes. The study considered 5 structural variables of greenspace which were species composition, tree density, tree size, vertical and horizontal structure, and tree layout pattern. A photo-questionnaire was prepared through color simulations of different landscape types for each structural variable. Preference responses of an interval-scale rating from 214 respondents were statistically analyzed between landscape types and between respondent groups. Respondents preferred greenspace landscapes with diverse tree species to single species, higher tree density to lower density, larger trees to many smaller trees, multilayered and grouped plantings to single-layered and sparse plantings, and informal pattern to formal pattern. These preferences tended to be relatively higher for educated specialist and student groups than for other generalist group. Thus, multilayered and dense plantings in natural pattern including larger trees of diverse species, which are similar to ecological plantings, are recommended to increase aesthetic function of greenspace.

• Design Convergence Study
• /
• v.14 no.2
• /
• pp.51-65
• /
• 2015

The purpose of this study is to derive the design characteristics of the pattern, which can effectively support the building facade design and to analyze the correlation of their characteristics. This paper deals with five different design patterns suggested by Ben Pell. They are the applied pattern, perforated pattern, layered pattern, casting pattern, and tiled pattern. This paper analyzes the design characteristics of the applied pattern, which shows the highest point in the previous survey. The 'continuous' has a high emotional correlation. The high correlation with the emotional word 'continuous' and 'regular' was derived. The final emotional design characteristic is 'continuous-discontinuous', and 'irregular-regular'. and these emotional words can be summarized as the relatively highest correlation. In this paper, it is worth analyzing design characteristics of building facade by a support of digital technology and discussing utilization of design characteristics derived.