• International Journal of Concrete Structures and Materials
• /
• v.9 no.4
• /
• pp.427-438
• /
• 2015

The present work proposes a new image analysis method for the evaluation of the multi-walled carbon nanotube (MWNT) distribution in a cement matrix. In this method, white cement was used instead of ordinary Portland cement with MWNT in an effort to differentiate MWNT from the cement matrix. In addition, MWNT-embedded cement composites were fabricated under different flows of fresh composite mixtures, incorporating a constant MWNT content (0.6 wt%) to verify correlation between the MWNT distribution and flow. The image analysis demonstrated that the MWNT distribution was significantly enhanced in the composites fabricated under a low flow condition, and DC conductivity results revealed the dramatic increase in the conductivity of the composites fabricated under the same condition, which supported the image analysis results. The composites were also prepared under the low flow condition (114 mm < flow < 126 mm), incorporating various MWNT contents. The image analysis of the composites revealed an increase in the planar occupation ratio of MWNT, and DC conductivity results exhibited dramatic increase in the conductivity (percolation phenomena) as the MWNT content increased. The image analysis and DC conductivity results indicated that fabrication of the composites under the low flow condition was an effective way to enhance the MWNT distribution.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.12
• /
• pp.3030-3037
• /
• 2013

Life time of facilities is different In case of operating environment and frequency of use. So, the durable year of the facilities is only considered to replace the facilities at present. Thus, system management is needed economical assesment based on condition evaluation through performance analysis of facilities. This research makes a proposal for scientific condition evaluation table through physical assessment, performance analysis assessment, durable years assessment about satellite communication facilities being used in K-water. Consequentially, reasonable replacement plan is established for satellite communication facilities.

• Journal of the Korean Society of Safety
• /
• v.30 no.5
• /
• pp.131-137
• /
• 2015

For the evaluation of safety margin of a nuclear power plant using a conservative methodology, the influence of applied assumptions such as initial conditions and boundary conditions needs to be assessed deliberately. Usually, a combination of the most conservative initial conditions is determined, and the safety margin for the transient is evaluated through the analysis for this conservative conditions. In existing conservative methodologies, a most-conservative condition is searched through the analyses for the maximum, minimum, and nominal values of the major parameters. In the present study, we investigates a new approach which can be applied to choose a most-conservative initial condition effectively when a best-estimate computer code and a conservative evaluation methodology are utilized for the evaluation of safety margin of transients. By constituting the band of various initial conditions using the random sampling of input parameters, the sensitivity study for various parameters are performed systematically. A method of sampling the value of control or operation parameters for a certain range is adopted by use of MOSAIQUE program, which enables to minimize the efforts for achieving the steady-state for various different conditions. A representative control parameter is identified, which governs the reactor coolant flow rate, pressurizer pressure, pressurizer level, and steam generator level, respectively. It is shown that an appropriate distribution of input parameter is obtained by adjusting the range and distribution of the control parameter.

• Asia Marketing Journal
• /
• v.21 no.4
• /
• pp.45-57
• /
• 2020

With the development of new technologies, virtual reality (VR) is emerging as a new consumer marketing platform. Yet, only a few studies have investigated VR in the consumption context. The current research explores how experiencing a product through VR influences consumer attitude and purchase intention for the product. Although assessing products in real life is believed to be more diagnostic than that through VR, the present research revealed that experiencing a product through VR could lead to a more positive attitude toward and higher purchase intention for the product. We also demonstrated that "enjoyment" has a mediating effect while evaluating the product through VR. To compare product experience through VR to that in real life, we employed the HTC Vive VR system to implement a VR environment. In the VR condition, participants evaluated plastic building blocks using a VR headset and a motion controller; and in the real life (reality) condition, they evaluted plastic building blocks printed using a 3D printer to make them look exactly the same as the blocks used in the VR condition. Finally, implications and suggestions are discussed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 1992.04a
• /
• pp.21-43
• /
• 1992

The recently-developed automated vessels require a system which evaluates the operating condition of the ship at present position form weather information as well as sensors; forecasts the operation condition the sea state to come in foreseeable future ; and suggests the optimum course and speed for ship's sa-fety. According to a study deck wetness propeller racing slamming rolling vertical acceleration lateral acce-leartion vertical bending moment at midship etc. were chosen as the factors for evaluating seakeeping per-formance. As a mater of fact there is no developing the hardware of a system which could consider all the factors onseakeeping performance. This study introduces a theoretical method which makes it possible to evaluate the seakeeping perfor-mance byapplying a theory from reliability engineering and thereby establishing a safety space. lation of stochastic processes with the factors presently adopted for evaluating sekakeeping performance. and develops the overall eseakeeping performance evaluation system in consideration of the safety of human being cargoes and the ship This method of evaluation shall be of much use in developing the practical system of seakeeping perfor-mance of a ship in waves.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.5 no.2
• /
• pp.137-146
• /
• 2001

The non-destructive tests are widely used to predict the strength of existing structures. The purpose of the present study is to propose the prediction equations for strength evaluation of concrete structures. The present study focuses on the rebound method and ultrasonic pulse velocity method for quartzite aggregate concrete. The major test variables include the water-cement ratio and curing methods. The water-cement ratio are 0.4, 0.5, 0.6, 0.7, respectively and the curing method covers ail-dry condition and standard curing condition. The prediction equations for strength of concrete are proposed from the present test data.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.1
• /
• pp.47-54
• /
• 2016

Microgrids offer several reliability benefits, such as the improvement of load-point reliability and the opportunity for reliability-differentiated services. The primary goal of this work is to investigate the impacts of operating condition on the reliability index for microgrid system. It relies on a component failure rate model which quantifies the relationship between component failure rate and state variables. Some parameters involved are characterized by subjective uncertainty. Thus, fuzzy numbers are introduced to represent such parameters, and an optimization model based on Fuzzy Chance Constrained Programming (FCCP) is established for reliability index calculation. In addition, we present a hybrid algorithm which combines scenario enumeration and fuzzy simulation as a solution tool. The simulations in a microgrid test system show that reliability indices without considering operating condition can often prove to be optimistic. We also investigate two groups of situations, which include the different penetration levels of microsource and different confidence levels. The results support the necessity of considering operating condition for achieving accurate reliability evaluation.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.187-192
• /
• 2000

The severity of drought could be evaluated by the accumulative rainfall method, soil moisture condition method, storage ratio method, and water supply restriction intensity method, etc. The pattern of drought could be forecast with the most similar pattern of accumulative rainfall out of the file of past rainfall history. The information that how much rainfall should be expected to overcome the present drought could be obtained from the reservoir storage ratio and soil moisture condition.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.181-183
• /
• 2013

In case of hydrological observation system, Life time of facilities is different with operating environment and frequency of use. So, the durable year of the facilities is only considered to replace the facilities at present. Thus, system management is needed economical assesment based on condition evaluation through performance analysis of facilities. This research makes a proposal for scientific condition evaluation table through physical assessment, performance analysis assessment, durable years assessment about satellite communication facilities being used in K-water. Consequentially, reasonable replacement plan is established for satellite communication facilities.

• Journal of the Korean Institute of Rural Architecture
• /
• v.16 no.1
• /
• pp.53-61
• /
• 2014

The purpose of this study is to analyze present condition and users' behavior on waterfront in local city. To analyze the current physical statues and behavioral issues, 3 cities including Jinju city(Nam river), Ulsan city(Taewha river), and Dae-gu city(Gumho river) has chosen as research areas, the questionnaire and field survey were conducted in research areas focusing on post occupancy evaluation. In this study, it was found that main behaviors of waterfront were rest and exercise and overall satisfactions of waterfront were related to the decision-making for revisitation. However, unsatisfactory physical factors of waterfront were the position and number of facilities related to the behaviors such as rest, exercise, and bicycle riding. Especially, most unsatisfactory factor was the inadequate lighting in respect of intensity of illumination and position although much people had been used each waterfronts at nighttime. In conclusion it was thought that it was necessary to reinforce the program related to culture and leisure such as public performance and to establish infrastructure related to life-time sport and various outdoor exercise for waterfront activation.