• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.3 s.303
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• pp.25-32
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• 2005

PLC is the most widely utilized among many sorts of existing controller for the design of process control system, and study about a PLC language is performed actively. In this paper, we proposed the method that we increase an output points when increased of the output machine which is going to control it in the FA design that used PLC. Output point is going to be extended with 2-3 points in the state that cannot equip output unit in basic base any more. Then an extension base, a power supply, an extension cable and an output unit must be equipped particularly. Then a cost must be added very much. This paper propose the method which extended an output in a small quantity. We designed the expansion unit that received the points of output unit and decoded the signal and the program module that finally extended output points by encoding and decoding, and we confirmed his feasibility through a experiment.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.9
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• pp.28-35
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• 2015

In this paper, we propose to identify redundant power states of high-level power model based on clock gating enable signals(CGENs) using dependencies of Boolean functions and structural dependencies of clock gating cells. Three functional dependencies between two CGENs, namely equvalence, inversion, and inclusion, are used. Functions of CGENs in a circuit are represented by binary decision diagrams (BDDs) and the functional relations are used to reduce the number of power states. The structural dependency appears when a clock gating cell drives another clock gating cells in a circuit. Automatic dependency checking algorithm has been proposed. The experimental results show the average number of power state is reduced by 59%.

• Journal of the Korean Geotechnical Society
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• v.20 no.4
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• pp.65-74
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• 2004

Based on the field measuring data obtained from seven excavation sections in Inchon International Airport Project, the horizontal displacement of sheet piling walls supported by anchors and the lateral earth pressure acting on sheet piling walls was investigated in soft ground. The proposed diagram of lateral earth pressure is a rectangular form, and the maximum earth pressure corresponds to $0.6\gamma H$. The maximum earth pressure is similar to the empirical earth pressure proposed by NAVFAC(1982). The quantitative safe criterion of sheet piling walls with struts is established from the relationships between increasing velocity of maximum horizontal displacement and stability number in excavated ground. If the velocity of maximum horizontal displacement shows lower than 1mm per day, the sheet piling walls exist under stable state. When the velocity of maximum horizontal displacement becomes more than 1mm and less than 2mm per day, excavation works should be observed with caution. Also, when the velocity of maximum horizontal displacement becomes more than 2mm per day, appropriate remediations and reinforcements are applied to sheet piling walls.

• Wind and Structures
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• v.25 no.2
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• pp.195-214
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• 2017

Full-scale wind characteristics based on the field measurements is an essential element in structural wind engineering. Statistical analysis of the wind characteristics at Sutong Cable-stayed Bridge (SCB) site is conducted in this study with the recorded long-term wind data from structural health monitoring system (SHMS) between 2008 and 2015. Both the mean and turbulent wind characteristics and power spectra are comprehensively investigated and compared with those in the current codes of practice, such as the measured wind rose diagram, monthly maximum mean wind speed, turbulence intensity, integral length scale. Measurement results based on the monitoring data show that winds surrounding the SCB site are substantially influenced by the southeast monsoon in summer and strong northern wind in winter. The measured turbulence intensity is slightly higher than the recommended values in specifications, while the measured ratio of lateral to longitudinal turbulence intensity is slightly lower. An approximately linear relationship between the measured turbulence intensities and gust factors is obtained. The mean value of the turbulence integral length scale is smaller than that of typical typhoon events. In addition, it is found that the Kaimal spectrum is suitable to be adopted as the power spectrum for longitudinal wind component at the SCB site. This contribution would provide important wind characteristic references for the wind performance evaluation of SCB and other civil infrastructures in adjacent regions.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.51-55
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• 2002

This study was to investigate the effect of EEG wave type of visual cortex on conjugate movement of eyeball according to movement of visual target. Visual evoked potential(VEP) system used the Bio-Pag(production in USA) and recorded to 586 computer. The illumination of test room was 50lux and the visual target was red light dot of 3cm size. The results of dextroversion and levoversion as follows : The visual stimulation waves on the visual cortex have about 71% of delta wave, about 12% of beta wave, about 9% theta wave and about 6% of alpha wave respectively. The dextroversion and levoversion state was similar results on the histogram amplitude of EEG wave, frequency of EEG wave type, EEG wave style and phase diagram of amplitude. Expecially the histogram amplitude of EEG wave appeared almost the Gaussian shape and the phase analysis of amplitude of EEG wave was nearly linear shape. On the fast fourier transform of the amplitude and Hz, the frequency was almost low frequency under 20 Hz, and the dextroversion and levoversion shape was similar results.

• Tribology and Lubricants
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• v.33 no.1
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• pp.9-14
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• 2017

This paper presents a rotordynamic analysis and the operation of a power turbine applied to a 250 kW super-critical $CO_2$ cycle. The power turbine consists of a turbine wheel and a shaft supported by two fluid film bearings. We use a tilting pad bearing for the power turbine owing to the high speed operation, and employ copper backing pads to improve the thermal management of the bearing. We conduct a rotordynamic analysis based on the design parameters of the power turbine. The dynamic coefficients of the tilting pad bearings were calculated based on the iso-thermal lubrication theory and turbine wheel was modeled as equivalent inertia. The predicted Cambell diagram showed that there are two critical speeds, namely the conical and bending critical speeds under the rated speed. However, the unbalance response prediction showed that vibration levels are controlled within 10 mm for all speed ranges owing to the high damping ratio of the modes. Additionally, the predicted logarithmic decrement indicates that there is no unstable mode. The power turbine uses compressed air at a temperature of $250^{\circ}C$ in its operation, and we monitor the shaft vibration and temperature of the lubricant during the test. In the steady state, we record a temperature rise of $40^{\circ}C$ between the inlet and outlet lubricant and the measured shaft vibration shows good agreement with the prediction.

• Journal of Internet Computing and Services
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• v.12 no.6
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• pp.161-170
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• 2011

Despite some practical confusion over the variations in the diagram which may be drawn differently depending upon the CASE, the statechart of UML has been widely used to show the dynamic behaviour of the systems. Prior research has employed either simple switch-case statement or the state design pattern to generate source code from the statechart, which may result in varying source codes. This paper made an attempt to formally define the statechart and generate source codes from it. Firstly we cleaned up the XMI which was generated from different CASEs. This XMI has been translated to the EHA to identify automata contained in it. Then the elements of the statechart metamodel were mapped to the java programs. We also verified the quality of source codes by measuring functionality and maintainability. The case employed in this study was the air conditioner. The reason was that the case includes various states and transitions of interest. It was found that XMI was well extracted by removing some legacy codes in the CASE and the source codes were then successfully generated with the concurrency and hierarchy of the statechart. Further research is required to validate it practical significance with a larger case.

• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.404-414
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• 2005

In the packet data network systems beyond 3G, the service quality of current users is affected by traffic load due to the packet burstiness. There also exists a hot cell problem, a well-known problem of cellular systems, caused by traffic centraliBation. Hot cell problem is one of the major reasons of degrading system performance because hot cell increases the call drop rate without fully utilization of system resource. Therefore, it is very important to distribute the traffic on the several neighboring cells so that system uses its resource effectively and maintains the quality of service. In this paper, we propose the adaptive handoff algorithms for distributing traffic in the packet data network systems. In addition, we propose a new load estimation method with MAC state diagram suitable for packet data network systems. Through the simulation results, we could find that proposed algorithm is able to improve efficiency of system resource and to assure the service quality of users through traffic distribution.

• Journal of the Korean Society for Heat Treatment
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• v.11 no.4
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• pp.305-314
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• 1998

This study has been performed to investigate into some effects of various amounts of $CO_2$ and CO gas added to the $50%NH_3-N_2$ based gas atmosphere on microstructure, hardness, chemical analysis and residual stress in the compound and diffusion layer of AISI H13 treated by gaseous nitrocarburising process. The compound layer formed in the surface is composed of mainly ${\varepsilon}-Fe_3$(N,C) and small amount of ${\gamma}^{\prime}-Fe_4N$ and cementite. The maximum hardness value obtainable from H13 steel is shown to be 1200 Hv and the effecvtive hardening depth increases with increasing CO content from 1% to 4%. In the case of CO content over 4%, however, it decreases with increasing CO content. The composition profiles of nitrogen and carbon are found to be within the ${\varepsilon}$-phase field located above the ${\varepsilon}+{\gamma}^{\prime}$ phase field in the Fe-N-C diagram. It is shown that the maximum value of compressive residual stress of H13 steel treated in atmospheres of $50%NH_3-(2,4)%CO_2-N_2-CO$ gas mixture is $48kg/mm^2$ and the depth to which residual stress is in Compressive state is $90{\mu}m$ for the atmosphere $50%NH_3-45%N_2-4%CO_2-1%CO$ gas mixture. It is consequently important to control the maximum value and size of compressive residual stress region in order to obtain desirable mechanical properties.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.446-446
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• 2011

One dimensional (1-D) structures of ZnO nanorods are promising elements for future optoelectronic devices. However there are still many obstacles in fabricating high-quality p-type ZnO up to now. In addition, it is limited to measure the degree of the doping concentration and carrier transport of the doped 1-D ZnO with conventional methods such as Hall measurement. Here we demonstrate the measurement of the electronic properties of p- and n-doped ZnO nanorods by the Kelvin probe force microscopy (KPFM). Vertically aligned ZnO nanorods with intrinsic n-doped, As-doped p-type, and p-n junction were grown by vapor phase epitaxy (VPE). Individual nanowires were then transferred onto Au films deposited on Si substrates. The morphology and surface potentials were measured simultaneously by the KPFM. The work function of the individual nanorods was estimated by comparing with that of gold film as a reference, and the doping concentration of each ZnO nanorods was deduced. Our KPFM results show that the average work function difference between the p-type and n-type regions of p-n junction ZnO nanorod is about ~85meV. This value is in good agreement with the difference in the work function between As-doped p- and n-type ZnO nanorods (96meV) measured with the same conditions. This value is smaller than the expected values estimated from the energy band diagram. However it is explained in terms of surface state and surface band bending.