• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1483-1493
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• 2018

Recently, more power facilities are needed to cope with the increasing electric demand. However, the additional construction of generators, transmission and distribution installations is not easy because of environmental problems and citizen's complaints. Under this circumstance, a microgrid system with distributed renewable resources emerges as an alternative of the traditional power systems. Moreover, the configuration of power system changes with more DC loads and more DC installations. This paper is written to introduce an idea of a genetic algorithm-based solution to determine the optimal capacity of the distributed generators depending on the types of system configuration: AC-link, DC-link and Hybrid-link types. In this paper, photovoltaic, wind turbine, energy storage system and diesel generator are considered as distributed generators and the feasibility of the proposed algorithm is verified by comparing the calculated capacity of each distributed resource with HOMER simulation results for 3 types of system configuration.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.571-579
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• 1997

There are some transmission types on the reverse link of wideband DS-CDMA cellular system. The configurations of logical channels on the reverse link may be different dependent upon the transmission methods of reverse pilot or control signaling. In this paper, we present three transmission types on the wideband DS-CDMA reverse link; no-pilot system, pilot-channel aided system and pilot-symbol aided system. And we compare the performance of three systems in terms of capacity and cell coverage. The pilot-symbol aided system is shown to have the better performance than the pilot-channel aided system in both capacity and cell coverage.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.29-32
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• 2001

This paper has simulated the PER(Packet Error Rate), ratio of received packet and payload BER of Bluetooth system with packet types of ACL(Asynchronous Connection Less) and SCO(Synchronous Connection Oriented) link over wireless Ad-hoc environment. AWGN(Additive White Gaussian Noise) and Rayleigh fading are considered as channel model, and the analysis is based on the baseband model of Bluetooth system. In terms of PER and ratio of received packet, performance of DM1 packet is almost same as those of HV1, HV2 and HV3 packets, the performances of the other packets depend on the packet types. In terms of payload BER performance, there is no difference among HV2 packet of SCO link and DM1, DM3, DM5 packets of ACL link. Moreover, there is no difference among HV3 packet of SCO link and DM1, DM3, DM5 packets of ACL link, too.

• Journal of the Semiconductor & Display Technology
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• v.4 no.3 s.12
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• pp.5-9
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• 2005

The bonding structure of organic materials such as fluorinated amorphous carbon films was classified into two types due to the chemical shifts. The electrical properties of fluorinated amorphous carbon films also showed very different effect of two types notwithstanding a very little difference. Fluorinated amorphous carbon films with the cross-link break-age structure existed large leakage current resulting from effect of the electron tunneling. Increasing the cation due to the electron-deficient group increased the barrier height of the films with the cross-link amorphous structure, therefore the electric characteristic of the final materials with low dielectric constant was also improved. The lowest dielectric constant is 2.3 at the sample with the cross-link amorphous structure.

• Journal of Power System Engineering
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• v.14 no.6
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• pp.47-53
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• 2010

A stabilizer link connects the stabilizer bar to the lower arm of the suspension. When a vehicle is turning, lateral forces from the tire are transmitted through the stabilizer link into the stabilizer bar. The stabilizer bar will twist, thus adding rigidity to the vehicle body. In this study, the stabilizer link body was manufactured by using composite material with POM-GF25%. Therefore, the strength evaluation of stability link body with composite material carried out from tensile, wear and fatigue test. The tensile strength between the stability link body with composite material and the rod with knurling was the largest of four types of rod. In Analyzing materials property using optical sensing technique of stabilizer link for automobile parts, its has been identified the safety.

• International Journal of Highway Engineering
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• v.17 no.3
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• pp.97-105
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• 2015

PURPOSES : The Toll Collection System (TCS) operated by the Korea Expressway Corporation provides accurate traffic counts between tollgates within the expressway network under the closed-type toll collection system. However, although origin-destination (OD) matrices for a travel demand model can be constructed using these traffic counts, these matrices cannot be directly applied because it is technically difficult to determine appropriate passenger car equivalent (PCE) values for the vehicle types used in TCS. Therefore, this study was initiated to systematically determine the appropriate PCE values of TCS vehicle types for the travel demand model. METHODS : To search for the appropriate PCE values of TCS vehicle types, a traffic demand model based on TCS-based OD matrices and the expressway network was developed. Using the traffic demand model and a genetic algorithm, the appropriate PCE values were optimized through an approach that minimizes errors between actual link counts and estimated link volumes. RESULTS : As a result of the optimization, the optimal PCE values of TCS vehicle types 1 and 5 were determined to be 1 and 3.7, respectively. Those of TCS vehicle types 2 through 4 are found in the manual for the preliminary feasibility study. CONCLUSIONS : Based on the given vehicle delay functions and network properties (i.e., speeds and capacities), the travel demand model with the optimized PCE values produced a MAPE value of 37.7%, RMSE value of 17124.14, and correlation coefficient of 0.9506. Conclusively, the optimized PCE values were revealed to produce estimates of expressway link volumes sufficiently close to actual link counts.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.777-781
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• 1997

One of the spring-link mechanisms, the air circuit breaker(ACB), was studied to improve the shock-proof characteristics of it. The low-cycle fatigue fracture phenomenon was occurred on the critical link, called h-link, of ACB for the repeated rapid closing and opening operations. To analyze the cause of failure, dynamic FE-analysis on the h-link part of ACB was accomplished with considered the velocity and acceleration of the links per time as boundary conditions, which were obtained by using ADAMS. Then, to reduce the maximum tensile stress on the h-link, three types of h-link were suggested and one of them was selected. Fmm this study, we suggested the process of analysis on the high-speed motion behavior part related low-cycle fatigue fractures.

• Archives of design research
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• v.16 no.1
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• pp.261-270
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• 2003

This paper focuses on the navigation methods which users select in different websites or for different tasks. Identifying the preferred navigation methods used for each case would help developers to construct the structure of website more effectively and confidently. To achieve the goal, this paper presents a framework on the classification of links as S_link and C_link. Then experiment is designed in order to evaluate the type of preferred link in each case. For the experiment, two different types of prototype websites such as news sites and shopping sites were constructed for which two different types of tasks such as goal-centered tasks and process-centered tasks were given to users. Particularly, to minimize the effects of visual elements and technical difference, prototype websites were produced with only HTML, not JavaScript nor Shockwave Flash. The result showed dearly that type of tasks had more significant effects on users navigation patterns than type of website. And users are more dependent on the S_link in the goal-centered task and on the C_link in the process-centered task. These findings were more apparent at the Qualitative test which was conducted for the comparative analysis between prototype site and real site.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.158-164
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• 2003

The air circuit breaker (ACB) with the spring-actuated mechanism was studied to improve the fatigue-proof characteristics of its link. The low-cycle fatigue fracture phenomenon occurred on the critical link, called h-link, of ACB from the repeated rapid closing and opening operations. To analyze the cause of failure, dynamic FE-analysis on the b-link part of ACB was performed considering tile velocity and acceleration of the links per time as boundary conditions, which were obtained by using ADAMS. Also, the S-N curve obtained by experiments was used to investigate requirement on the fatigue-proof characteristics. Then, to reduce the maximum tensile stress on the h-link, three types of h-link were examined and one of them was selected.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.67-72
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• 2005

The bonding structure of organic materials such as fluorinated amorphous carbon films was classified into two types due to the chemical shifts. The electrical properties of fluorinated amorphous carbon films also showed very different effect of two types notwithstanding a very little difference. Fluorinated amorphous carbon films with the cross-link breakage structure existed large leakage current resulting from effect of the electron tunneling. Increasing the cation due to the electron-deficient group increased the barrier height of the films with the cross-link amorphous structure, therefore the electric characteristic of the final materials with low dielectric constant was also improved. The lowest dielectric constant is 2.3 at the sample with the cross-link amorphous structure.