• Journal of information and communication convergence engineering
• /
• v.16 no.1
• /
• pp.38-42
• /
• 2018

In this paper, we consider measurement allocation problem in a spatially correlated sensor field. Our goal is to determine the probability of each sensor's being measured based on its contribution to the estimation reliability; it is desirable that a sensor improving the estimation reliability is measured more frequently. We consider a spatial correlation model of a sensor field reflecting transmission power limit, noise in measurement and transmission channel, and channel attenuation. Then the estimation reliability is defined distortion error between event source and its estimation at sink. Motivated by the correlation nature, we model the measurement allocation problem into a cooperative game, and then quantify each sensor's contribution using Shapley value. Against the intractability in the computation of exact Shapley value, we deploy a randomized method that enables to compute the approximate Shapley value within a reasonable time. Besides, we envisage a measurement scheduling achieving the balance between network lifetime and estimation reliability.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1957-1958
• /
• 2008

The Logic Built In Self Test (LBIST) technique is substantially applied in chip design in most many semiconductor company in despite of unavoidable overhead like an increase in dimension and time delay occurred as it used. Currently common LBIST software uses the MISR (Multiple Input Shift Register) However, it has many considerations like defining the X-value (Unknown Value), length and number of Scan Chain, Scan Chain and so on for analysis of result occurred in the process. So, to solve these problems, common LBIST software provides the solution method automated. Nevertheless, these problems haven't been solved automatically by Tri-state Bus in logic circuit yet. This paper studies the simulator and algorithm that judges whether Tri-state Bus lines is the circuit which have X-value or One-hot Value after presuming the control signal of the lines which output X-value in the logic circuit to solve the most serious problems.

• Wind and Structures
• /
• v.31 no.3
• /
• pp.197-207
• /
• 2020

Knowledge on the design value of extreme wind pressure coefficients (EWPC) of a specific zone of buildings is essential for the wind-resistant capacity of claddings. This paper presents a method to estimate the representative EWPC introducing the multivariate extreme value model. The spatial correlations of the extreme wind pressures at different locations can be consider through the multivariate extreme value. The moving average method is also adopted in this method, so that the measured point pressure can be converted to wind pressure of an area. The proposed method is applied to wind tunnel test results of a large flat roof building. Comparison with existing methods shows that it can give a good estimation for all target zones with different sizes.

• International conference on construction engineering and project management
• /
• 2013.01a
• /
• pp.129-132
• /
• 2013

Determining on a particular construction method is typically decided in the initial phases of a project. However, changing conditions during actual construction may require a different method or technology to be employed. Providing an option for project managers to change construction provides flexibility that can increase value to the overall project. This research provides the ability to modify construction methods as a real option, which allows its value to be modeled. The research also formalizes a way to integrate a binomial lattice model with the Earned Value Method's S-curve. The integrated model provides a decision support tool that planners can use to determine whether to exercise the option depending on the status metrics provided by EVM.

• Journal of Power System Engineering
• /
• v.12 no.3
• /
• pp.72-77
• /
• 2008

This study was investigated to know the effect of Cu addition on austempered ductile cast iron at various temperatures and times. Test results showed that the volume fraction of retained austenite and the carbon contents of retained austenite showed the greatest value at $400^{\circ}C$. Also, in case of specimens having more Cu contents, the volume fraction of retained austenite and the carbon contents of retained austenite showed the lower value. After austempering treatment, tensile strength and Impact value increased, but elongation decreased. With increasing austempering treatment temperature, tensile strength, elongation, and impact value decreased. In case of specimen having more Cu contents, tensile strength showed the higher value, but elongation showed the lower value. Damping capacity was decreased by austempering treatment and was not affected on austempering temperature and time. In case of specimen having more Cu contents, damping capacity showed the higher value.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2002.09a
• /
• pp.28-34
• /
• 2002

The b-value in the magnitude-frequency relationship logN(m) = $\alpha$ - bmwhere N(m) is the number of earthquakes exceeding magnitude m, is important seismicity parameter In hazard analysis. Estimation of the b-value for earthquake data observed on KSRS array network is done employing the maximum likelihood technique. Assuming the whole Korea Peninsula as a single seismic source area, the b-value is computed at 0.9. The estimation for KMA earthquake data is also similar to that. Since estimate is a function of minimum magnitude, we can inspect the completeness of earthquake catalog in the fitting process of b-value. KSRS and KMA data lists are probably incomplete for magnitudes less than 2.0 and 3.0, respectively. Examples from probabilistic seismic hazard assessment calculated for a range of b-value show that the small change of b-value has seriously effect on the prediction of ground motion.

• Korean Journal of Construction Engineering and Management
• /
• v.5 no.4 s.20
• /
• pp.147-154
• /
• 2004

Project value can be increased by implementing the most suitable one or more Value Management Processes (VMP). For the past decades, a variety of innovative management processes have been increasingly introduced into the construction industry. Each VMP is considered to be significantly beneficial for capital facility projects to proactively achieve one or more project value objectives. This paper covers the compilation of the 44 VMPs and provides their leveraging project characteristics that require the implementation of one or more VMPs. The results of data collection establish relative importance between the VMPs and the project characteristic factors in collaboration with 51 experts from both industry and academia. In the lack of industry awareness of both VMPs and their causal factors, the results of this study can facilitate the implementation of the VMPs and ultimately enhance the value of a particular capital project.

• Journal of Power System Engineering
• /
• v.12 no.1
• /
• pp.47-52
• /
• 2008

This study was investigated the effect of subzero treatment in austempered ductile cast iron. Retained austenite transformed to martensite by subzero treatment and strain. With decreasing subzero treatment temperature and increasing strain, retained austenite transformed more to martensite and transformed 30% above by subzero treatment at $-196^{\circ}C$. With decreasing subzero treatment temperature, the value of strength and ratio of increasing of strength, hardness and ratio of increasing of hardness increased but the value of elongation and ratio of decreasing of elongation decreased. With decreasing subzero treatment temperature, impact value and ratio of decreasing of impact value decreased. In case of subzero treatment at $-196^{\circ}C$, hardness value increased about 18% and impact value decreased above 20%. We could find that in subzero treated specimens had a little of effect on the tensile properties but had very much effect on the hardness and value of the impact.

• Applied Chemistry for Engineering
• /
• v.29 no.4
• /
• pp.440-445
• /
• 2018

In this study, the stability of O/W cosmetic facial cream emulsions according to HLB values was evaluated by mixing nonionic surfactants, such as Brij 78&72 and Brij 98&92. Brij 78&72 (steareth-20&steareth-2, EMS-01), saturated fatty acid, and Brij 98&92 (oleth-20&oleth-2, EMS-02), unsaturated fatty acid, were used as mixed surfactants. The stability of the O/W emulsion was evaluated by using the emulsion viscosity, particle size, particle size distribution, and zeta-potential. The viscosity of the emulsion increased with the increase of time for EMS-01 while that of EMS-02 decreased with the increase of HLB value. The particle size of both EMS-01 and EMS-02 increased with time. The emulsifier with a HLB value of 10.8, which is the most similar to the required HLB value of mineral oil, 10.5, had the smallest particle size and highest density and also showed the highest emulsion stability. The zeta-potential of both emulsions tended to increase with the HLB value. No significant changes were observed in emulsions of the HLB value of 10.8 or more. The saturated fatty acid system, EMS-01, exhibited a higher zeta-potential value than that of the unsaturated fatty acid EMS-02 and also was superior in the stability.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.13 no.3
• /
• pp.9-15
• /
• 2017

In this study, set values of PICV(Pressure Independent Control Valve) were simulated according to the pressure distribution and velocity. The higher the set value and the open rate, as the lower the pressure in the neck. On the contrary, the lower the set value and open rate, as the higher the pressure in the neck. When the set value was small, the pressure was distributed sufficiently and confirmed that the pressure was generated by the VOF, confirming that it could generate a vapor pressure. When the set value 100 %, the lower corn open rate of the differential pressure was 46 % to 29 %, set value 100 % was 29 % to 19 %, and set value 6 % was 12 % to 6 % for the lower corn open rate percentile, it was limited to within 50 %. Thus, the results of this study on the correlation between open rate and differential pressure of the set value of the PICV will be beneficial to improve performance of flow control valves and contribute to their efficient operation used for a hydronic system.