• Journal of Digital Contents Society
• /
• v.5 no.4
• /
• pp.251-256
• /
• 2004

The flatness of a silicon wafer concerned with ULSI chip is one of the most critical parameters ensuring high yield of wafers. That is necessary to constitute the circuit with high quality for he surface of silicon wafer, which comes to be base to make the direct circuit of the semiconductor, Flatness, therefore, is the most important factor to guarantee it wafer with high quality. The process of polishing is one of the most crucial production line among 10 processing stages to change the rough surface into the flatnees with best quality. Currently at this process, it is general for an engineer in charge to observe, judge and control the model of wafer from the monitor of measuring equipment with his/her own eyes to enhance the degree of flatness. This, however, is quite a troublesome job for someone has to check of process by one's physical experience. The purpose of this study is to approach the model of wafer with digital contents and to apply the result of the research for an algorithm which enables to control the polishing process by means of measuring the degree of flatness automatically, not by person, but by system. In addition, this paper shows that this algorithm proposed for the whole wafer flatness enables to draw an estimated algorithm which is for the thickness of sites to measure the degree of flatness for each site of wafer.

• The Journal of Society for e-Business Studies
• /
• v.17 no.2
• /
• pp.63-72
• /
• 2012

The Korean telecommunications market has been expanding swiftly, these days, to be saturated. In this environment, the upcoming mobile telecommunication market, where 4G service was introduced this year, is becoming more substitutive and competitive. Thus, the demand forecasting of 4G service is very difficult, while it is critical to market success. This paper adopts a multi-generation diffusion model to capture the diffusion and substitution patterns for two successive generation of technological services, i.e., 3G and 4G mobile telecommunications services. The three parameters, i.e., the coefficient of innovation, the coefficient of imitation, and the coefficient of market potential, used in the multi-generation diffusion model based on Norton and Bass[11] are obtained by inference from similar substitutive relations between older and newer telecommunication services to 3G and 4G services. The simulation results show that the Bass type multi-generation model can be successfully applied to the demand forecasting of newly introduced 4G mobile telecommunication service.

• Nuclear Engineering and Technology
• /
• v.52 no.11
• /
• pp.2460-2470
• /
• 2020

To study the thermophysical and neutronic properties of thorium-plutonium fuel, a conceptual design of a hybrid facility consisting of a subcritical Th-Pu reactor core and a source of additional D-D neutrons that places on the axis of the core is proposed. The source of such neutrons is a column of high-temperature plasma held in a long magnetic trap for D-D fusionreactions. This article presents computer simulation results of generation of thermonuclear neutrons in the plasma, facility neutronic properties and the evolution of a fuel nuclide composition in the reactor core. Simulations were performed for an axis-symmetric radially profiled reactor core consisting of zones with various nuclear fuel composition. Such reactor core containing a continuously operating stationary D-D neutron source with a yield intensity of Y = 2 × 10¹⁶ neutrons per second can operate as a nuclear hybrid system at its effective coefficient of neutron multiplication 0.95-0.99. Options are proposed for optimizing plasma parameters to increase the neutron yield in order to compensate the effective multiplication factor decreasing and plant power in a long operating cycle (3000-day duration). The obtained simulation results demonstrate the possibility of organizing the stable operation of the proposed hybrid 'fusion-fission' facility.

• Corrosion Science and Technology
• /
• v.11 no.6
• /
• pp.213-217
• /
• 2012

The amount of spent fuel from nuclear power plants has been increasing. An effective management plan of the spent fuel becomes a critical issue, because the storage capacity of each plant will reach its storage limit in a few years. The volume of high toxic spent fuel can be reduced through a fuel processing. Advanced Fuel Cycle (AFC) system is considered to be one of the options to reduce the toxicity and volume of the spent fuel. It is necessary to set up a test facility to demonstrate the feasibility of the process at the engineering scale. The objective of the work is a development of the safety evaluation technology for the AFC system. The evaluation technology of the AFC structural integrity and processes were surveyed and reviewed. Key evaluation parameters for the main processes such as electrolytic reduction, electrorefining, and electrowinning were obtained. The survey results may be used for the establishment of the AFC regulatory licensing procedure. The establishment of the licensing criteria minimizes the trials and errors of the AFC facility design. Issues taken from the survey on the regulatory procedure and design safety features for the AFC facility provide a chance to resolve potential issues in advance.

• Korean Journal of Applied Biomechanics
• /
• v.16 no.1
• /
• pp.1-10
• /
• 2006

The purpose of this study was to identify critical parameters of a putting performance using jerk cost function. Jerk is the time rate of change of acceleration and it has been suggested that a skilled performance is characterized by decreased jerk magnitude. Four elite golfers($handicap{\leq}2$) and 4 novice golfers participated in this study for the comparison. The 3D kinematic data were collected for each subject performing 5 trials of putts for each of these distances (random order): 1m, 3m, 5m The putting stroke was divided into 3 phases such as back swing. down swing and follow-through. In this study, it was assumed that there exist smoothness difference between elite and novice golfers during putting. The distance and jerk-cost function of Putting stroke for each phase were analyzed Results showed that there was a significant difference in jerk cost function at putter toe (at media-lateral direction) and at the center of mass between two groups by increasing putting distance. From these it could be concluded that jerk can be used as a kinematic parameter for distinguishing elite and novice golfers.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2008.11a
• /
• pp.207-211
• /
• 2008

The importance of cost management in early stage has been increasing due to market change and competition severence in construction industry. Because the adjustable budget is only 20% after finishing design stage, the critical decision is made in the early stage. However, in the early stage, the design information is not enough to make crucial decision. Therefore, this research suggests the predicting method on the purpose of accurate cost estimation. The parametric estimation is appropriate for the early stage, especially it has the strength of rapidity in cost estimation. This research analyzes 84 actual data of public apartment on the scale of $11{\sim}15$ stories, and then performs the correlation analysis between cost and influence factors. After eliminating the parameters which causes the problem of multicollinearity, this research derived the formula through the multi-regression analysis.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.3
• /
• pp.200-205
• /
• 2013

Pretreatment process is the critical step of RO (Reverse Osmosis) membrane desalination plant in order to prevent RO membrane fouling. The pretreatment as a key component of RO process must be designed to produce a constant and high quality RO feedwater which has low silt density index (SDI). This experiment was conducted to assess parameters affecting SDI value, such as pH, seawater turbidity, temperature, and coagulant dose. The experimental results indicated that the source seawater turbidity did cause little effects on SDI values of filtered water. The 0.45 um hydrophilic membrane was more appropriate than the hydrophobic membrane for measuring SDI. The SDI value was increased with decreasing pH under the condition of below pH 7.0. In addition, the water temperature significantly affected the SDI values, showing higher SDI value with lower water temperature.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.42 no.9 s.339
• /
• pp.49-56
• /
• 2005

Memory effect, which influence the performance of Doherty amplifier, become more significant and critical in designing these circuits as the modulation signal bandwidth and operation power level increase. This paper reports on an attempt to investigate, model and quantity the contribution of the electrical nonlinearity effects and the thermal memory effects to a Doherty amplifier's distortion generation. Also this raper reports on the development of an accurate dynamic expression of the instantaneous junction temperature as a function of the instantaneous dissipated power. This expression has been used in the construction of an electrothermal model for the Doherty amplifier. Parameters for the nelv proposed behavior model were determined from the Doherty amplifier measurements obtained under different excitation conditions. This study led us to conclude that the effects of the transistor self-heating phenomenon are important for signals with wideband modulation bandwidth(ex. W-CDMA or UMTS signal). Doherty amplifier with electrothermal memory effect compensator enhanced ACLR performance about 20 dB than without electrothemal memory effect compensator. Experiment results were mesured by 60W LDMOS Doherty amplifier and electrothermal memory effect compensator was simulated by ADS.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.12
• /
• pp.1-9
• /
• 2000

A new method, the external resistance method (ERM method), is proposed for accurate extraction of the gate bias-dependent effective channel carrier mobility (${\mu}_{eff}$) and separated parasitic source/drain resistances ($R_S$ and $R_D$) of n-channel MOSFET's. The proposed ERM method is applied to n-channel LDD MOSFETs with two different gate lengths ($W_m/L_m=30{\mu}m/0.6{\mu}m,\;30{\mu}m/1{\mu}m$) in the linear mode of current-voltage characteristics ($I_D-V_{GS},\;V_{DS}$). We also considered gate voltage dependence of separated $R_2$ and $R_D$ in the accurate modeling and extraction of effective channel carrier mobility. Good agreement of experimental data is observed in submicron n-channel LDD MOSFETs. Combining with capacitance-voltage characteristics, the ERM method is expected to be very useful for accurate and efficient extraction of ${\mu}_{eff},\;R_D,\;R_S$, and other characteristic parameters in both symmetric and asymmetric structure MOSFET's in which parasitic resistances are critical to the improvement of high speed performance and reliability.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.4 no.2
• /
• pp.100-105
• /
• 2004

The influencing factors on the OPC (optical proximity correction) results are quantitatively analyzed using OPCed L/S patterns. ${\sigma}$ values of proximity variations are measured to be 9.3 nm and 15.2 nm for PR-A and PR-B, respectively. The effect of post exposure bake condition is assessed. 16.2 nm and 13.8 nm of variations are observed. Proximity variations of 11.6 nm and 15.2 nm are measured by changing the illumination condition. In order not to seriously deteriorate the OPC, these factors should be fixed after the OPC rules are extracted. Proximity variations of 11.4, 13.9, and 15.2 nm are observed for the mask mean-to-targets of 0, 2 and 4 nm, respectively. The decrease the OPC grid size from 1 nm to 0.5 nm enhances the correction resolution and the OCV is reduced from 14.6 nm to 11.4 nm. The enhancement amount of proximity variations are 9.2 nm corresponding to 39% improvement. The critical dimension (CD) uniformity improvement for adopting the small grid size is confirmed by measuring the CD uniformity on real SRAM pattern. CD uniformities are measured 9.9 nm and 8.7 nm for grid size of 1 nm and 0.5 nm, respectively. 22% improvement of the CD uniformity is achieved. The decrease of OPC grid size is shown to improve not only the proximity correction, but also the uniformity.