• Structural Engineering and Mechanics
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• v.49 no.1
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• pp.65-80
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• 2014

This paper reports on the development of a minimum cost design model and its application for obtaining economic designs for reinforced High Strength Concrete (HSC) T-sections in bending under ultimate limit state conditions. Cost objective functions, behavior constraint including material nonlinearities of steel and HSC, conditions on strain compatibility in steel and concrete and geometric design variable constraints are derived and implemented within the Conjugate Gradient optimization algorithm. Particular attention is paid to problem formulation, solution behavior and economic considerations. A typical example problem is considered to illustrate the applicability of the minimum cost design model and solution methodology. Results are confronted to design solutions derived from conventional design office methods to evaluate the performance of the cost model and its sensitivity to a wide range of unit cost ratios of construction materials and various classes of HSC described in Eurocode2. It is shown, among others that optimal solutions achieved using the present approach can lead to substantial savings in the amount of construction materials to be used. In addition, the proposed approach is practically simple, reliable and computationally effective compared to standard design procedures used in current engineering practice.

• KIEAE Journal
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• v.16 no.3
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• pp.129-135
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• 2016

Purpose: Building figuration is imperative to perceive the its value, environmental clean status and form. Therefore, maintenance activities of the building exterior are required to keep the housing condition and value. Each household should pay the repair cost which is brought out in the future. For this repair cost, the estimation model would needed to forecast and provide the required cost. This study aimed at providing the estimation model of the repair cost, using the repair survey data between the 2011 and 2014 in Seoul. Method: For these, it took various estimation function of repair cost such as 1st function, inverse function and so on. These above functions would be applied into the building exterior and outdoor facilities which figure the building shape and characteristics. Result: Results of this study are shown ; First, among 11 estimation models, the power function has a better statistics and goodness-of-fit than any other models. Second, the estimation model with a variable of household has a pattern in upward to the right. On the contrary, the model with management area is little downward to the right. Both of them are depended on the estimated parameter of the power function and the parameter smaller than 1.

• Journal of Korean Academy of Nursing Administration
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• v.13 no.2
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• pp.199-207
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• 2007

Purpose: Clinical characteristics and medical cost were analyzed according to the surgical procedures for intertrochanteric fracture in aged patients to assess the appropriateness of treatment expense and to find possibility of reducing the medical cost. Method: Variable for the statistical analysis were; the clinical characteristics, medical cost according to the surgical procedures, the treatment success rate, the total medical expense, and the average expense per case. SAS Package Version 8.02. was used to analyze the relevant data. Results: Operative procedures differ significantly according to the gender and by the location of institution. Only significant clinical variables according to the operative procedure were duration of general anesthesia and amount of blood transfusion. Average cost per treatment was the highest in the bipolar hemiarthroplasty followed by the gamma nail and hip compressing screw. Average cost for bipolar hemiarthroplasty was significantly higher than other surgical procedures. Conclusions: The difference in hospital costs for treatment of intertrochanteric fracture originates from the utilized surgical procedures, mostly by the materials used. The method of surgical treatment should be carefully determined by the purpose of the surgery, in order to improve the quality of medical care and also to reduce the hospital cost.

• Design & Manufacturing
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• v.2 no.6
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• pp.23-27
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• 2008

It is well known that the family-mold has an advantage to reduce the cost for production and mold. However, defects are frequently occurred by over packing the smaller volume cavity during molding, especially when the family-mold has a volumetric difference between two cavities. In this study, the cavity-filling imbalance was confirmed by the temperature and the pressure sensors, and a variable-runner system was developed for balancing the cavity-filling. Experiments of balancing the cavity filling was carried out in the family-mold with the variable-runner system, and balancing the cavity-filling was confirmed by changing the cross-sectional area of a runner in the variable-runner system with the temperature and pressure sensors. The influence of the injection speed to the balancing-capability of the variable-runner system was also examined in the experiment.

• Journal of IKEEE
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• v.20 no.4
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• pp.385-391
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• 2016

We demonstrated experimentally a variable optical frequency comb source using a cascaded dual parallel Mach Zehnder modulator (DPMZM) and a phase modulator (PM). With this simple configuration and applying low drive voltages, we generated variable comb source composed of spectral lines 3, 5, 7, 9 and 11 with 10-GHz frequency spacing, also generated 2 and 3 spectral lines with 20 GHz frequency spacing. The generated comb source maintains high spectral coherence across the entire bandwidth with good spectral flatness (within 1-dB for 2, 3, 5, 7 comb lines, within 2-dB for 9-comb lines and within 3-dB for 11 comb lines). The flat and variable comb source is mainly achieved by manipulating 6 operating parameters of DPMZM, setting RF amplifier gain, connected at phase modulator and phase shifters. Hence the method is simple and offers great flexibility in achieving flat and variable comb spectrum, which is experimentally demonstrated. This brings advantages of power efficiency due to low driving voltages, simplicity and cost effectiveness to the system.

• Transactions of Materials Processing
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• v.17 no.2
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• pp.130-134
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• 2008

Resource and energy saving is a very important practice for the future as well as for today. Weight saving of structural parts, which are formed by extrusion, plays a key role in manufacturing field. The cross-sections of extruded parts with industrial aluminum are constant in the axial direction by conventional extrusion method. Especially, these aluminum parts used and manufactured in the car industry need other processes to vary the cross-section in the axial direction. However, applications of these parts are often limited by high cost. If the cross-section of the parts is variable by only extrusion with newly developed method, the application of extruded aluminum parts will actually increase. Therefore, a new CNC extruder that can control the section area of a car part was invented for the first time in the nation. Using the extrusion machine, the experiment was performed to validate its workability during the variable section extrusion process. Also, numerical analysis was carried out to investigate the flow mode with different speeds of main ram and various pocket shapes of a die-set in the variable section extrusion process.

• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.41-50
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• 2013

Economic feasibility study using weighted average variable Jeju System Marginal Price, SMP, was conducted for Gasiri wind farm of Jeju Island. To predict the variable Jeju SMP, generator share ratio for SMP was calculated from the real time wind power production and the power demand data for years. Also, sensitivity analysis on Net Present Value, NPV, and Benefit/Cost Ratio, B/C ratio, were performed to clarify which factors are more important in assessing economic feasibility. The result shows that the Gasiri wind farm has a minimum of 110 billion won and a maximum of 132 billion won difference between fixed and variable SMP. Also, Capacity Factor, C.F., had the highest sensitivity for NPV, followed by SMP. Accordingly, when economic analysis for a potential wind farm site is carried out, the variable SMP as well as C.F. should be considered for more accurate assessment of the wind farm.

• The Journal of the Korea Contents Association
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• v.16 no.5
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• pp.113-123
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• 2016

Purpose: The purpose of this study was to evaluate how the cost perception and the cost attitude of nurses have effect on cost management behavior. Methods: Participants were 150 nurses who had worked for more than 1 year in general hospitals. Data were collected from November 16 to December 11, 2015, using self-recorded questionnaires. Collected data were analyzed using descriptive statistics and multiple regression methods. Results: Cost management behavior was positively correlated with cost perception and cost attitude. Cost attitude was revealed as the variable having effect on cost management behavior. Positive cost attitude can induce desirable cost management. Conclusion: It is necessary to develop effective and systematic Cost Education Program for nurses. Our result is useful to develop cost Education program of clinical nurses, and can be expandable for a variety of fields in programs for nursing students, and nurse managers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.853-858
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• 2019

One of the methods which can enhance the efficiency of railroad network is construction of interconnection branch line for several route to share one railway. In Korea, this method already has been implemented or excuted as project level. This study suggests a network design model and a solution algorithm to choice most proper site to construction it and determine the priority of branch lines which can be considered in planning level, not project level. The model is a non-linear optimization program which minimize total cost-construction cost, operating cost and passengers' travel cost. The decision variables are a binary variable to explain whether construction or not and its direction and a integer variable of the frequencies of travel routes. The solution algorithm-problem solution and route choice and also the result of implementation for example network are suggested. This result can be more advanced after application in real network and calibration of parameters.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.183-193
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• 2007

Traditionally, a congestion charge based on first-best congestion pricing theory, namely, the theory of marginal cost pricing theory, is equal to the difference between marginal social cost and marginal private cost. It is charged on each link so as to derive a user equilibrium flow pattern to a system optimal one. Based on this theory this paper investigates on the characteristics of first-best congestion pricing of multiple user class on road with variable demand, and presents two methods for analysis of social and spatial equity. For these purposes, we study on the characteristics of first-best congestion pricing derived from system optimal in time and in monetary unit, and analyze equity from this congestion pricing with an example network.