• Journal of the military operations research society of Korea
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• v.22 no.1
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• pp.67-80
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• 1996

Artificial Intelligence(AI) techniques and Object-Oriented(OO) techniques contribute to the simulation modeling of the complex systems. AI techniques are suitable to model human reasoning in the simulation. While OO techniques have advantages of re-usability, maintainability and extendability of the software. Thus, in this paper, we design a knowledge-based object-oriented simulation model, particularly for the logistics analysis of military armor vehicles. The simulation model consists of three modules i.e., scenario, simulation mechanism, and inference engine. The model is designed within the OO paradigm and implemented by using the C++ language. An example case of using the model for the logistic analysis is included.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.4 s.310
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• pp.39-49
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• 2006

This paper proposes an efficient verification environment of PCI Express controller that is the future I/O interface. This verification environment consists of a test vector generator, a test bench, and two abstract memories. We also define the assembler set to generate the verification scenarios. In this paper, we propose the random test environment which consists of a random vector generator, a .simulator part, and a compare engine. This verification methodology is useful to find the special errors which are not detected by the basic-behavioral test and hardware-design test.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.4
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• pp.256-267
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• 2014

An automatic switch among ensembles of clustering algorithms is proposed as a part of the bibliographic big data retrieval system by utilizing a fuzzy inference engine as a decision support tool to select the fastest performing clustering algorithm between fuzzy C-means (FCM) clustering, Newman-Girvan clustering, and the combination of both. It aims to realize the best clustering performance with the reduction of computational complexity from O($n^3$) to O(n). The automatic switch is developed by using fuzzy logic controller written in Java and accepts 3 inputs from each clustering result, i.e., number of clusters, number of vertices, and time taken to complete the clustering process. The experimental results on PC (Intel Core i5-3210M at 2.50 GHz) demonstrates that the combination of both clustering algorithms is selected as the best performing algorithm in 20 out of 27 cases with the highest percentage of 83.99%, completed in 161 seconds. The self-adapted FCM is selected as the best performing algorithm in 4 cases and the Newman-Girvan is selected in 3 cases.The automatic switch is to be incorporated into the bibliographic big data retrieval system that focuses on visualization of fuzzy relationship using hybrid approach combining FCM and Newman-Girvan algorithm, and is planning to be released to the public through the Internet.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.111-112
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• 2009

Diamond-like carbon (DLC) is a convenient term to indicate the compositions of the various forms of amorphous carbon (a-C), tetrahedral amorphous carbon (ta-C), hydrogenated amorphous carbon and tetrahedral amorphous carbon (a-C:H and ta-C:H). The a-C film with disordered graphitic ordering, such as soot, chars, glassy carbon, and evaporated a-C, is shown in the lower left hand corner. If the fraction of sp3 bonding reaches a high degree, such an a-C is denoted as tetrahedral amorphous carbon (ta-C), in order to distinguish it from sp2 a-C [2]. Two hydrocarbon polymers, that is, polyethylene (CH2)n and polyacetylene (CH)n, define the limits of the triangle in the right hand corner beyond which interconnecting C-C networks do not form, and only strait-chain molecules are formed. The DLC films, i.e. a-C, ta-C, a-C:H and ta-C:H, have some extreme properties similar to diamond, such as hardness, elastic modulus and chemical inertness. These films are great advantages for many applications. One of the most important applications of the carbon-based films is the coating for magnetic hard disk recording. The second successful application is wear protective and antireflective films for IR windows. The third application is wear protection of bearings and sliding friction parts. The fourth is precision gages for the automotive industry. Recently, exciting ongoing study [1] tries to deposit a carbon-based protective film on engine parts (e.g. engine cylinders and pistons) taking into account not only low friction and wear, but also self lubricating properties. Reduction of the oil consumption is expected. Currently, for an additional application field, the carbon-based films are extensively studied as excellent candidates for biocompatible films on biomedical implants. The carbon-based films consist of carbon, hydrogen and nitrogen, which are biologically harmless as well as the main elements of human body. Some in vitro and limited in vivo studies on the biological effects of carbon-based films have been studied [$2{\sim}5$].The carbon-based films have great potentials in many fields. However, a few technological issues for carbon-based film are still needed to be studied to improve the applicability. Aisenberg and Chabot [3] firstly prepared an amorphous carbon film on substrates remained at room temperature using a beam of carbon ions produced using argon plasma. Spencer et al. [4] had subsequently developed this field. Many deposition techniques for DLC films have been developed to increase the fraction of sp3 bonding in the films. The a-C films have been prepared by a variety of deposition methods such as ion plating, DC or RF sputtering, RF or DC plasma enhanced chemical vapor deposition (PECVD), electron cyclotron resonance chemical vapor deposition (ECR-CVD), ion implantation, ablation, pulsed laser deposition and cathodic arc deposition, from a variety of carbon target or gaseous sources materials [5]. Sputtering is the most common deposition method for a-C film. Deposited films by these plasma methods, such as plasma enhanced chemical vapor deposition (PECVD) [6], are ranged into the interior of the triangle. Application fields of DLC films investigated from papers. Many papers purposed to apply for tribology due to the carbon-based films of low friction and wear resistance. Figure 1 shows the percentage of DLC research interest for application field. The biggest portion is tribology field. It is occupied 57%. Second, biomedical field hold 14%. Nowadays, biomedical field is took notice in many countries and significantly increased the research papers. DLC films actually applied to many industries in 2005 as shown figure 2. The most applied fields are mold and machinery industries. It took over 50%. The automobile industry is more and more increase application parts. In the near future, automobile industry is expected a big market for DLC coating. Figure 1 Research interests of carbon-based filmsFigure 2 Demand ratio of DLC coating for industry in 2005. In this presentation, I will introduce a trend of carbon-based coating research and applications.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.8
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• pp.1552-1565
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• 1992

Three dimensional numerical calculations were carried out for two different combustion chambers with the offset valve in order to investigate the swirl and the squish effects on the flow fields. The modified K-.epsilon. turbulence model considering the change of the density under the condition of the rapid compression and expansion of the pistion was used. During the compression process, it was found that the squish flow which controls the subsequent combustion process was produced due to the piston bowl in the bowl piston type combustion chambers but not for the flat piston type. The swirl velocity close to the solid body rotation was maintained in the flat piston type combustion chambers, but for the bowl piston type a resulting from the change of the solid body rotation was generated in the radial-circumferential plane. For the swirl ratio effect, as the swirl ratio increases, it was found that a large and strong vortex was generated in the radial-circumferential plane of bowl piston type combustion chambers because of the strong inward flows from the combustion chamber wall. These computational results were compared with the results of LDA measurement.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.6
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• pp.9-19
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• 1998

RAID technology that provides the disk I/O system with high performance and high availability is essential for OLTP server. This paper describes the design and implementation of the HIPSS RAID system that has been developed for the SPAX OLTP server. HIPSS has the following design objectives: high performance, high availability, standardization and modularization of external interface, and ease of maintenance. It guarantees high performance by providing 10 independent I/O channels, large data cache, and parity calculation engine. Hardware modularization of the host interface makes it easy to replace host interface hardware module. By providing dual power supply, dual array controller, and disk hot swapping, it provides the system with high availability Implementation of HIPSS and integration test on SPAX has been completed and performance measurement on HIPSS is now going on. In this paper, we provide the detail description for HIPSS system architecture and the implementation results.

• Journal of Climate Change Research
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• v.6 no.4
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• pp.319-330
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• 2015

This study was carried out to predict the optimal growth site and estimate carbon stocks of Quercus acuta, evergreen broad-leaved trees in warm temperate zone according to climate change. The criterion for the optimal site prediction was created by quantification method with quantitative and qualitative data, collected from growth factors of stands and environmental factors of survey sites of 42 plots in Q. acuta by study relationship between growth of tree and site environmental factors. A program for the optimal site prediction was developed by using GIS engine tools. To prediction of the suitable growth site of Quercus acuta, developed program in this study applied to Wando in Jeollanam-do, distributing a various evergreen bread-leaved trees of warm temperate zone. In the results from analysis of the optimal site prediction on Q. acuta, the characteristics of the optimal site showed as follows; site environmental features of class I (the best site class for Q. acuta) was defined as 401 ~ 500 m of altitude, $21{\sim}25^{\circ}$ of slope with above hillside, residual of deposit convex of slope type with west of aspect. The area and carbon stocks of optimal site prediction by class for Q. acuta in classI showed 147.1 ha (2.5%), total 316.5 tC/ha, total $1,161tCO_2/ha/yr$ of class I, 2,703.5 ha (46.3%), total 5,817.4 tC/ha, total $21,331tCO_2/ha/yr$ of class II, 2,845.5 ha (48.6%), total 6,123.0 tC/ha, total $2,845.5tCO_2/ha/yr$ of class III and 153.7 ha (2.6%), total 330.7 tC/ha, total $1,213.7tCO_2/ha/yr$ of class IV.

• Journal of Biosystems Engineering
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• v.15 no.4
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• pp.310-318
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• 1990

The amount of grain loss incurred during harvesting operation through the chaff-outlet of combine may not be negligible. To minimize this grain loss and optimize condition of combining, it may be necessary that the amout of chaff-outlet loss dependent on varying crop condition is to be estimated as exactly as possible. This study was thus intended to develop the monitor that could indicate the amount of grain lost through the chaff-outlet of combine during haravesting operation, and to find out driving and operating method of combine that could reduce chaff-outlet loss. In the study(1), the frequency distributions of each sound generated by the impact of kernels and chaff, the sound generated by the impact of the mixture of kernels and chaff, and vibration or noise created by the combine engine and other moving parts were investigated experimentally. Based on the results of frequency analyses, the loss monitor was developed which could measure the impact sound of paddy kernels that could be distinguished from those of other threshing products through chaff-outlet, and from vibration or noise created by the combine engine and other moving parts. Also in this study, detecting capability of monitor was tested by comparing the amount of grain lost through chaff-outlet with the amount of grain detected by the loss monitor, and changes in chaff-outlet grain loss on the increase of traveling speed, location of chaff-outlet loss control plate and variety of paddy rice were measured using the loss monitor. The monitor developed in this study efficiently measured the amount of grain lost through the chaff-outlet of combine. It was found that the chaff-outlet grain loss ratio was affected greatly by the variety of paddy rice, the location of chaff-outlet loss control plate and traveling speed of combine.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.819-826
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• 2000

This study was performed to develop a measurement system of tractor field performance for plow and rotary operations. Measurement system for tractor consisted of torque sensors to measure torque of drive axles and PTO axle, speed sensors to measure rotational speed of drive axles and engine, microcomputer to control data logger, and data logger as I/O interface system. The measurement system was installed on four-wheel-drive tractor. Four-element full-bridge type strain gages were used for torque measurement of drive axles and optical encoders were used to measure speeds of drive axles and engine. Slip rings were mounted on the rotational axles. Signals from sensors were inputted to data logger that was controlled by microcomputer with parallel communication. Sensors were calibrated before the field tests. Regression equations were found on completion of the calibrations. The field experiment was performed at paddy fields and uplands. Rotary and plow were used when the tractor was operated in the field. Travelling speeds of the tractor were 1.9 km/h, 2.7 km/h, 3.7 km/h, 5.5 km/h, 8.2 km/h, and 11.8 km/h. Operating depths of implements were maintained approximately 20cm during the tests. Torque data of drive axles were different at each location during plow and rotary operations. Results showed that torque of rear axles were greater than those of front axles. Total torque were 6860 - 11064 Nm at the upland and 7360 - 14190 Nm at the paddy field for plow operations. It was found that torque at the paddy field were about 20% greater than those at the upland for plow operations. Torque data showed that rotary operations required less power than plow operation at the paddy field and the upland. Torque measurements at each axle for rotary operations were only 8 - 16% of plow operations in the upland and 15 - 20% in the paddy field.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.73.1-73.1
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• 2010

For the successful cold starting of a fuel cell engine, either internal of external heat supply must be made to overcome the formation of ice from water below the freezing point of water. In the present study, switchable vanadium oxide compounds as variable temperature-electrical resistance materials onto the surface of flat metallic bipolar plates have been prepared by a dip-coating technique via an aqueous sol-gel method. Subsequently, the chemical composition and micro-structure of the polycrystalline solid thin films were analyzed by X-ray diffraction, X-ray fluorescence spectroscopy, and field emission scanning electron microscopy. In addition, it was carefully measured electrical resistance hysteresis loop over a temperature range from $-20^{\circ}C$ to $80^{\circ}C$ using the four-point probe method. The experimental results revealed that the thin films was mainly composed of Karelianite $V_2O_3$ which acts as negative temperature coefficient materials. Also, it was found that thermal dissipation rate of the vanadium oxide thin films partially satisfy about 50% saving of the substantial amount of energy required for ice melting at $-20^{\circ}C$. Moreover, electrical resistances of the vanadium-based materials converge on an extremely small value similar to that of pure flat metallic bipolar plates at higher temperature, i.e. $T{\geq}40^{\circ}C$. As a consequence, experimental studies proved that it is possible to apply the variable temperature-electrical resistance material based on vanadium oxides for the cold starting enhancement of a fuel cell vehicle and minimize parasitic power loss and eliminate any necessity for external equipment for heat supply in freezing conditions.