This is the pre-study to pile up the basic technique for the electro-discharge machining in the field of micro-drilling. The machined chips are flowed out from the machining area by the flow arisen from the high speed rotation of the electrode. The cylindrical shape electrode, whose diameter is 0.5mm, is clamped by the three point clamping type clamper and the clamper is attached at the front shaft of the high speed rotating DC motor. The current for machining is controlled by pulse width modulation technique and the machining conditions such as frequency and duty ratio are changed to find out the effect of the variables for machined results.

The voice coil actuator uses the Lorentz force between the magnetic field of the permanent magnets and the electromagnets to the motions and positioning. The small size, light weight and fast dynamic response of the these type actuators lead to admit them in the micro-positioning apparatus of the micro-machining systems. In this paper, the linear motion voice coil actuator is developed for the driving and positioning the rotating electrode of the electric discharge machine (EDM). The analyzed and measured results for the actuator are compared and discussed.

Active damping system is generally used for the vibration suppression and precise motion control for the flexible structure. This application can be easily found on the space structure and driving mechanism of optical storage devices. Although a control system using the flexible structure has many advantages over using rigid mechanism in driving energy saving, system weights, and etc., more complex and precise control strategies are required. A position control system using flexible structure and the concept of active damper is designed and manufactured, which is driven by slide DC motor and moving coil motor located at the tip of the flexible beam. Dynamic characteristics of this system are investigated by analytic and experimental ways. By the comparison of those two results, a nominal reference model for this system is proposed.

Rotary bending fatigue tests were carried out to investigate the fatigue behavior of high performance ductile cast iron experienced super rapid induction heat treatment. The effect of super rapid induction treatment on fatigue limit was experimentally examined with the special focus on the variation surface microstructure and the fatigue crack initiation and propagation through fractography. Main results obtained are as follows. By super rapid induction treatment in FCD500, the martensite structure obtained through conventional quenching heat treatment was confirmed on the specimen surface. The fatigue crack initiation in the hardened surface layer was restricted by the martensite structure and compressive residual stress. Thus, it could be interpreted that the initiation stress would be increased by the improvement of surface structure. The fatigue crack propagation in the hardened layer was retarded by the presence of the globular shape martensite around the graphite nodule and compressive residual stress. The crack propagation path has shown zigzag pattern in the hardened surface layer.

This paper presents a method for evaluating the performance of a leaf spring suspension and an air spring suspension systems for trucks in terms of ride and handling. Leaf springs, which generally have non-linear progressive force-deflection characteristics, are modeled using beam and contact elements. The leaf spring analysis model shows good correlation with experimental results. Each component of an air spring suspension system, which is a single leaf, air spring, height control valve, compressor and linkages, is modeled appropriately. Non-linear characteristics of air spring are accounted for using the measured data, and pressure and volume relations for height control system is also considered. The wheel rate of the air suspension is taken lower but roll stiffness is taken higher than those of leaf springs to improve ride and handling performance, which is verified through driving simulations.

Vehicle suspensions can be regarded as interconnection of rigid bodies with kinematic joints and compliance elements such as springs, bushings, and stabilizers. Design of a suspension system requires detailed specification of the interconnection point (or so called hard points) and characteristic values of compliance elements. During the design process, these design variables are determined to meet some prescribed performance targets expressed in terms of SDFs (Static Design Factors), such as toe, camber, compliance steer, etc. This paper elaborates on a systematic approach to achieve optimum design of suspension systems.

This research has an object to find out how the position of inlet valve influence swirling and tumbling of turbulence inside the combustion chamber of 4 valve engine. The computational analysis of three dimensional complicated turbulence flow in the cylinder is done by the KIVA-3V program to carry out this object. One use 6 valve positions with the bowl type of piston cavity. The swirl ration and the tumbling ratio of flow filed are evaluated quantitatively to find out how each valve position influence flow phenomena in the combustion chamber during the intake and compression processes.

This study is to analyze turbulent flow over a backward-facing step in a rectangular duct. The side wall effects on the internal flow were determined by varying the aspect ratio(defined as the step span-to-height ratio) from 1 to 20. In the flow behind a backward-facing step, separation, recirculation and redeveloping is occurred frequently. These phenomena appear in a particular variation by varying the aspect ratio. The results show that the aspect ratio has an influence on the velocity and reattachment length. When the AR is increased, the reattachment length is increased. For 6 over aspect ration, the rate of increase is decreased. The length of recirculation in the upper corner is increased, as the increase of aspect ration. It's width is not changed in the variation of aspect ration. The transverse, streamwise and spanwise velocities were decreased along the flow down stream of the step.

The mechanical properties including forming limit and deep-drawability of commercially-used sheet metals were experimentally estimated in this study. Uniaxial tensile test to obtain basic mechanical properties was carried out, followed by limiting dome height (LDH) test and forming limit diagram (FLD) test to quantitatively evaluate the sheet-formability. Deep drawing and reverse drawing tests were also performed to find out the critical values of the blank holding force and the gap between the die and the blank holder which enabled the deep drawing and reverse drawing of a successful cop without any wrinkle or fracture. The thickness of the cup wall along the rolling-, transeverse- and $45^{\circ}$-directions was measured and compared with one another. And the punch force-stroke curve and the critical punch force expected from the theory coincided with the experimental result very well for mild steel while not for aluminium alloy.

Rotary bending fatigue tests were performed to investigate the effects of 2-phase matrix structure on fatigue limit with prepared specimens in high strength ductile irons. Two types of the specimens with different microstructures have been used. Series A has sorbite and series B has bainite. Fatigue limits of both specimens are improved comparing with as cast specimen. The fatigue limit is higher in series B than in series A. The reason why the fatigue limit of series A shows inferiority to that of series B is due to the transition of micro fatigue cracks to mesocrack occurs very rapidly, so increased stress intensity factor drives the fatigue crack growth. The higher fatigue limit of series B which has bainite is caused by the ${\gamma}$ layer contained in microstructure impede the rapid growth of micro fatigue crack to mesocrack and ${\alpha}$ layer around graphite has the higher capacity for the absorption of plastic deformation energy than sorbite.

We have developed a power line simulator which is one of the basic tools for the research of the power line communication and its control system. In the developed simulators, we have considered the transfer function of the power line, noises and signal attenuation characteristics. Simulator was made using the matlab tool program. We made the power line modern using the FSK chip(ST7537) and experimentalized to show the efficiency grade of simulator. We have expected that the developed simulators are very useful in the area for the power line communication research and the control system design.

The dock is the most important resource in shipbuilding yard. Among the shipbuilding schedules, the ship erection schedule in a dock is preferentially built. As results of it, the other schedules(machining in plants, block assembly, pre-painting, pre-rigging, painting and etc) are made. In this study, ship erection scheduling is formulated using ILOG Scheduler. This study is to develop a new problem solving method for ship erection to make an effective schedule based on Constraint Satisfaction Technique(CST).

Ultra thin $Ta_2O_5$ gate dielectrics were prepared by RTMOCVD (rapid thermal metal organic chemical vapor deposition) using Ta source $TaC_{12}H_{30}O_5N$ and $O_2$ gaseous mixtures. As a result, $Ta_2O_5$ thin films showed significantly low leakage current compared to $SiO_2$ of identical thickness, which was due to the stabilization of the interfacial layer by NO ($SiO_xN_y$) passivation layer. The conduction of leakage current in $Ta_2O_5$ thin films was described by the hopping mechanism of Poole-Frenkel (PF) type.

The microstructural evolution during mechanical alloying of elemental Fe and Si powders, average composition $Fe_{30}Si_{70}$ and $Fe_{50}Si_{50}$, has been investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Differential scanning calorimetry (DSC). Mechanical alloying was performed by using a SPEX 8000 Mixer/Mill under argon atmosphere with/without hexane as a process control agent (PCA). In the presence of PCA, the milling process was dominated by fracture resulting in the decrease in particle size to about $1{\mu}m$. The structural development with milling time depended on the average composition of starting powders. The mixture of $Fe_{50}Si_{50}$ and $Fe_{30}Si_{70}$ resulted in the formation of FeSi(${\varepsilon}$ - phase) and $FeSi_2$(${\beta}$ - phase), respectively. In the case of $Fe_{33.3}Si_{66.7}$, a mixture and $FeSi_2({\beta})$ was formed. These results were discussed by considering the thermodynamics and kinetics concerning the milling process.

Current design and analyzing methods about soil nailing structures, developed on the basis of results obtained from experiments in laboratory or in field and numerical analyses, have applied different interaction mechanisms between the reinforced nails and the surrounding ground, and this different safety factors against failure have been obtained. They might be proper approached if the assumptions about rigidity of nails and ground conditions are met with actual conditions occurred in field. Otherwise, they would result in designing on analyzing in inappropriate ways so that it is needed to evaluate the validity of them. Therefore, overall behavior and failure mechanism about soil nailing system were investigated by performing numerical method. Using a finite element analysis, parametric studies were made to examine the importance of the various parameters and their effects on the soil nailing system. The numerical technique of FEM, implemented with Hyperbolic constitutive model, was also used to analyze the test results.

This paper is a research about system identification which optimizes uncertain geothechnical properties from the data measured during geotechnical design and construction. Various numerical optimization algorithms of Simplex method, Powell method, Rosenbrock method and Levenberg-Marquardt method were applied to the excavation problem to determine which method showed the best results with respect to robustness of success in finding an optimal solution to within a certain accuracy and number of function evaluations. From the results of numerical analysis, all of four algorithms are converged to exact solution after satisfying the allowed criteria, and Levenberg-Marquardt's algorithms was identified to be the most efficient method in number of function evaluations. System identification was applied to geotechnical engineering problems, possibly being occurred in field, to verify its applicability : estimation of settlement due to self-weight consolidation in dredged and filled soil. For self-weight consolidational settlement of a dredged soil, a program of evaluating the constitutive relationship of effective stress-void ratio-permeability was developed by using the technique of system identification. Thus, consolidational characteristics of a dredged soil, having a very high initial void ratio, can be evaluated.

This thesis is to investigate the sliding behavior of cantilever retaining wall by using the commercially available program of FLAC to simulate its behavior numerically. Cantilever retaining walls with flat base, sloped base and base with shear key, uniform surcharges being applied on the surface of backfill, were investigated to figure out appropriate location of shear key beneath the base of wall and, thus, its applicability to field condition was assessed by comparing the analyzed results to each other. On the other hand, previously performed centrifuge model test results (Eum, 1996) were analyzed numerically with FLAC to compare test results with respect to characteristics of load-settlement of surcharges and load-lateral movement of wall. Based on the failure mechanism observed during centrifuge tests, limit equilibrium method of finding the ultimate load inducing the sliding failure of wall was used to compare with values of the ultimate load obtained from conventional method of limit equilibrium method. Therefore, appropriate location of shear key was determined to mobilize the maximum resistance against sliding failure of wall.

The soil loss by rainfalls or runoffs has been one of the main environment problems in 20th century. The soil loss cause the various problems those are decreasing of the agricultural productivity, desolating of pasture land and disturbing of water flowing. Therefore, it is very important to measure properly various factors those are affecting to soil loss and to recognize a seriousness of soil loss problem. In this study, we use the USLE(Universal Soil Loss Equation) as a basic approaching way for soil loss analysis in a watershed, and the GSIS(Geo-Spatial Information System) technique is applied to evaluate for factors those are related to the USLE. The results of this study are consisted of three parts those are to build up the various topographical information that is needed for analysis of wide area soil loss by using the USLE, to evaluate the factors those are needed to the USLE, to estimate the soil loss condition of subbasin in the watershed.

In the last few years the automatic classification of morpholgical landforms using GSIS and DEM was investigated. Particular emphasis has been put on the morphological point attribute approaches and the extraction of drainage basin variables from digital elevation models. The automated derivation of landforms has become a neccessity for quantitative analysis in geomorphology. Furthermore, the application of GSIS technologies has become an important tool for data management and numerical data analysis for purpose of geomorphological mapping. A process developed by Dikau et al, which automates Hanmond's manual process, was applied to the pyoung chang of the kangwon. Although it produced a classification that has good resemblance to the landforms in the area, it had some problems. For example, it produced a progressive zonation when landform changes from plains to mountains, it does not distinguish open valleys from a plains mountain interface, and it was affected by micro relief. Although automating existing quantitative manual processes is an important step in the evolution automation, definition may need to be calibrated since the attributes are oftem measured differently. A new process is presented that partly solves these problems.

This study is conducted on the flexural toughness and flexural fatigue test to fine the mechanical properties of steel fiber reinforced rapid-set cement concrete. Experimental investigation is examined according to fiber contents(0, 0.4, 0.7, 1.0, 1.5%), fiber aspect ratio(58, 60, 83), fiber type (hooked, crimped fiber), and cement type (normal portland & rapid-set cement). The principal results obtained through this study are as follows; toughness and fatigue resistance tend to considerably increase with fiber contents, fiber aspect ration. And hooked fiber is improved better than crimped fiber. Concrete using rapid set cement is increased strength properties compared with concrete using normal portland cement, but relative strength properties behavior and fatigue resistance show a tendency to decrease a little.

In many areas of technology there are machines and systems controllable in up to six degrees of freedom. Helicopters and underwater vehicles, industrial robots are among the first representatives of this category. They need six degrees of freedom in order to move and orient within their workspace. An even broader and more explosively growing area is 3D computer graphics and virtual environment. In this work, functions of 3D input device are described and two types of commercial 3D input device are presented. Then, a preliminary experiment of a low cost 6 axis force/moment sensor is presented that can also be sued as a 3D input device. A low cost force/moment sensor and its application in robot teaching experiment is described. It computes the direction of 3 components of the force and 3 components of the moment applied by human holding the sensor by hand. The concept is shown by an experiment where the tool position and orientation of a robot in 3 dimensional space is controlled by the proposed sensor.

The computer pattern sewing machine is an automatic sewing machine that is controlled by an input pattern. Even a novice can run this machine for various tasks fast and reliably such as sewing a button, a belt ring and an airbag, etc. The pattern processing software, which is the main software of this machine, is for editing and modifying pattern data by online teaching or off-line editing, setting up parameters, and calculate a moving distance of working area on the x-y axes. In this paper we propose an algorithm to generate pattern data for sewing by simplifying image data. The pattern data are composed of outline data like dot, line, circle, arc, curve, etc. We need converting this data into sewing data which involve sewing parameter, moving distance of working are an the x-y axes, thread, spindle speed.

A study on the separation Cu, Ni, and Co was carried out using LIX 84 leachate, chelate extractant. For this test, artificial test solution was prepared by varing concentrations of Cu, Ni, Co, $(NH_4)_2CO_3$ and $(NH_4)_2SO_4$. It found that pH of the solution was very important factor for the separation of nickel from copper. The results showed that nickel was effectively extracted from copper by using LIX 84 at pH 1.0 to 1.2. The volume ration or organic to aqueous phases was 1.0. According to the McCabe-Thiele diagram, the extraction rate of copper was 99 percents at the equal ratio of organic to aqueous phase in three stages.

The process of localization of cracks and movement of the fracture process zone(FPZ) was studied using the acoustic-emission(AE) techniques. The rate of AE events and sources of AE activity were studied for mortar and rock specimens loaded in uniaxial compression. A series of transducers could be used to detect and AE activity. Based on the time differences between detection of the event at different transducers, source of AE activity could be detected. The rate of AE events increased sharply before peak load. The highest rate occurred just after peak load was attained. The effective crack length estimated from the modified linear-elastic fracture mechanics seemed consistent with the optical and AE measurements.

In this paper, we proposed a modofied genetic algorithm to minimize misclassification rate for determining the codebook. Genetic algorithms are adaptive methods which may be used solve search and optimization problems based on the genetic processes of biological organisms. But they generally require a large amount of computation efforts. GAVQ can choose the optimal individuals by genetic operators. The position of individuals are optimized to improve the recognition rate. The technical properties of this study is that prevents us from the local minimum problem, which is not avoidable by conventional VQ algorithms. We compared the simulation result with Matlab using phoneme data. The simulation results show that the recognition rate from GAVQ is improved by comparing the conventional VQ algorithms.

A single phase to three phase power converter with cost effective and simple structure is proposed. The converter consists of rectifier and inverter. The rectifier is composed of a half wave rectifier, a dc link capacitor, and a current limiting inductor, and the inverter is of only two switches with PWM control. For negative sequence operation the inverter output voltage leads the line input by $60^{\circ}$, and for positive sequence operation the inverter output voltage leads by $60^{\circ}$. We can see that positive sequence operation shows higher output voltage, slight harmonic distortion(2%), and better performances such as high efficiency and high power factor. A mathematical model for system analysis is provided, and specifications for selection and control scheme both for start-up and for steady state are analyzed. comparison and operational limits of positive and negative sequence operation are performed, and simulations and experiments are executed to verify the proposed.

Simple equations which can predict "exact" values of the natural frequency of vibration for the special orthotropic laminates are presented. Many laminates with certain orientations have decreasing values of $B_{16}$ and $B_{26}$ as the number of plies increases. Such laminates, with $D_{16}=D_{26}{\rightarrow}0$, including the laminates with anti-symmetric configurations can be solved by the same equation for the special orthotropic laminates. If the quasi-isotropic constants are used, the equations for the isotropic plates can be used. Use of some coefficients cab produce "exact" value for laminates with such configurations. Natural frequencies of the plate with varying aspect ratios is presented.

Vibration analysis for some of simple supported antisymmetric composite laminated plate loaded uniformly distributed axial force and attached mass was carried out. Because it is complicated to analysis this type of plate by theory of antisymmetric laminate, possibility for application of theory of special orthotropic laminate was studied, and natural frequency of laminated plate attached mass was calculated. Stiffness $B_{16}$, $B_{26}$, $D_{16}$, $D_{26}$ for this type of antisymmetric laminated plate converge on zero as the number of ply increases and it is possible to use classical theory by reason that considered plate has quasi-homogeneity without relevance to variation of angle. Difference between results by theory of antisymmetric and special orthotropic laminate is 0.36~1.96%, therefore it is convenient to analyze this by use of theory of special orthotropic laminate. When composite laminated plate with attached mass is analyzed range that was able to neglect self-weight of plate was proposed.

The joint in the concrete pavement provides a control against transverse or longitudinal cracking at slab, which may be caused by temperature or moisture variation during or after hydration. Without control of cracking, random crack may cause more serious distresses and result in structural or functional failure of pavement system. Sometimes, joint itself, purposed to control crack, may cause a distresses in joint due to its inherent weakness in structural integrity. Thus, the load transfer capacity in joint is very important for serviceability and durability. The purpose of this dissertation was to develop an evaluation system at joints of jointed concrete pavement using finite element analysis was performed using ILLI-SLAB program with a selected variables which might affect fairly to on the performance of transverse joints. The most significant variables were selected from precise analysis. It was concluded that the variables which most significantly affect to pavement deflections are the modulus of subgrade reaction(K) and the modulus of dowel/concrete interaction(G), and limiting criteria on the performance of joints at JCP at 300pci, 500,000 lb/in. respectively.

Two thermodynamic models were used to predict the partial molar volumes of solutes in supercritical carbon dioxide at infinite dilution: (1) the Peng-Robinson equation of state with various mixing rules including those based on $EOS/G^E$ (2) the Kirkwood Buff fluctuation integral with the hard sphere expansion (HSE) method. The Kirkwood-Buff fluctuation integral method, in which an equation of state for pure component and molecular parameters are required, produced better results especially near the critical point than the Peng-Robinson equation of state with the several mixing rules based an $EOS/G^E$. When the $EOS/G^E$ mixing rules were used, poorer results were obtained compared with the classical mixing rule and Kirkwood-Buff model.

It is a main object to find out the effect of curvature of pipe on the thermal flow field in copper pipe. the toroidal coordinate system is chosen for this project. 3-D numerical works are done by a commercial code, PHOENICS. The flow and temperature field are simulated and analysed on the view point of variation of pressure and temperature with Dean number. The results show that the strong recirculation phenomena and secondary flow are established and then a lot of pressure drop along main flow direction occurs at the curved portion of pipe and the temperature variation has a reversed trend of pressure variation along the axis of pipe.

When a variety of repeated loads are given, most steel structures failed in much lower level of loads than static failure loads. In addition, bridge always includes the internal defects or discontinuities. from these, fatigue cracks initiates and can lead to sudden failure. Thus, in this study, tensile specimens by the cover plate shapes were used as the test specimens. The fatigue test was performed by constant amplitude fatigue loading and beach mark. From the results of this study, each specimen's fatigue section was observed. in addition, stress intensity factor at crack tip was calculated by using the Green's function which applied to discontinuous section where causing stress concentration. Therefore, the fatigue life of structural detail was investigated by adopting the theories of fracture mechanics. each specimen's crack shape is a semi-elliptical surface crack or center crack sheet, stress gradient correction factor, Fg is the most subjective of all stress intensity correction factors and fatigue life should be predicted by previous proposed function and finite element analysis.

An integrated sewer management system was developed for the analysis of sewer flow and for optimal operation of sewer works using ArcView and SWMM. SWMM and ArcView were dynamically linked together using Avenue in order to construct user-friendly management system. The developed system was applied to a residential area in Choonchun city to verify its utilities. All the relevant field data were analyzed on the basis of developed system, and the modeling of sewer flow was implemented using RUNOFF, EXTRAN, TRANSPORT in SWMM. This system is now in the process of connection to the management system of watershed and surface environment in order to develope an integrated environmental management system. Futhermore, this system will be a critical part of overall control system of sewer works including sewer line and wastewater treatment plant. As this system can provide comprehensive prediction of flow and pollution profiles, it could serve as a tool not only for optimal management, but also for decision support system to examine the efficiency of planning and implementation of sewer projects.

This study was performed to develop an information processing system for the sound conservation of soil and groundwater resources. The system contains the geographic spatial information system(GSIS), and the numerical model of groundwater flow and contamination. Numerical models (MODFLOW, MOC3D, MT3D, PMPATH, PEST, UCODE) and GSIS(ArcView) were integrated for the construction of an integrated management system of subsurface environment. The developed system was applied to the management of three mineral water companies located in clean mountain area. The impact of pumping over the overall catchment basin was modeled using the developed system for the decision of future management criteria.

This paper is aimed at the development of comprehensive environmental management system, which can be operated on the basis of world wide web. This study has been initiated as a topic of G7 project in 1988, and will be accomplished in 2001. Even thought there should be lots of works remaining to achieve this goal, preliminary products can be summarized as follows : 1) integrated environments information management system, 2) web based control engine, 3) surface water environment management system, 4) subsurface water environment management system, 5) sewer and waterworks management system. The core methodology of the engine is the generalized multidimensional finite element matrices to depict the terms in the analysis of various partial differential equations. Spatial information management system (ArcView) and Visual Basic were extensively employed to construct GUI oriented web based engine. Developed systems were consist with very intense computer codes due to the necessity of combinatory management of environmental problems. The web based engine could be served as a decision tool for the integrated management of environmental projects in Korea.

The purpose of this paper is to study the effects of container size with multi-stage and multi-item on average inventory and customer service level in Kanban systems. We use the different distributions of demand and interarrival time for each item to show that we had better to change the container size depending on different type of item for this simulation study. The small lot size can be used for container size of a single item if there is no setup time. The container size should be identical with average order size as setup time increases. The fill rate increases if the container size is large with multi-item. However, it is difficult to establish the effective container size because the effects of the container size on the order queue time are not clear. It is suitable to use the average order size as the container size for each item if the variance of demand and interarrival time of each item is relatively small. It is effective to sue the average container size if the variance of them is relatively large.

Steel railway bridge gets vibration from moving load ; additionally, this kind of moving load is going to be a sufficient reason, which causes fatigue damage to steel railway bridge. Fatigue damage and stress curve were raised by moving load depends on span length in steel railway bridge. In other words, stress curve appears index regarding every axial load in short span, but self weight lets stress curve's change decrease in proportion to increasing span length. Thereby, we have studied that how the steel railway bridge appear fatigue damage in proportion to span length of steel railway bridge. Dynamic strain was measured in 4 steel plate-girder railway bridge during the trains was passing, which is located on the line of Kyoung-chun railway. And time history response analysis has been done in order to ensure actual survey. The results of this study show the decreased of the fatigue damage in steel railway bridge according to length of span. This paper ends is bases research of fatigue design in steel railway bridges according to span length.

An automated manufacturing process mechanism for string musical instruments has been designed in this study. In contrast to other manufacturing products, classical string instruments try to preserve their traditional design shapes even in these days and involve variety of wood working(carpentry) characteristics including highly skilled curved surfaces treatments. Great efforts have been put to develop an integrated and automated system for improved product quality and process control, reduced physical labors, better safety etc. They, however, have been limited to devise jigs and tools with regard to selected processes due to lack of technology and research man-powers. We carefully examined the products and process characteristics, and an automated mechanism which overcome prevailing drawbacks has been derived.

We analyzed theoretically the removal efficiency and the particle growth inside the pulse corona discharge reactor to remove $NO_x$ and investigated the effects of process variables such as the NO and $NH_3$ input concentrations. Most of NO is converted into $NO_2$ and $HNO_3$ and the $HNO_3$ reacts with $NH_3$ to form the $NH_4NO_3$ particles. About 6.4% of NO is converted into $HNO_2$ which form the $NH_4NO_2$ particles by reaction with $NH_3$. Some of $NO_2$ follows the reaction pathway to form $NO_3$ and $N_2O_5$. The amount of particles formed inside the reactor is basically determined by the input $NH_3$ concentration. The ratio of NO to $NH_3$ affects the reactor length for particle formation significantly. The higher the input concentrations of NO and $NH_3$ are, the faster the particles grow.

The separation of humic acid by ultrafiltration was most influenced by pressure difference. when pressure difference increased from latm to 3atm, permeate flux increased from 40% to 60% but rejection rate reduced from 97% to 91% because of adsorption of molecules of humic acid at membrane surface. Since physical adsorption was more dominant than chemical adsorption, adsorption of membrane surface was reduced 50% when slow rate increased at same conditions.

If the tactile sense is introduced to engineering and industries, it may provide more realistic virtual tactile sensing to human and it is possible to develop product that satisfy various consumer's taste. This paper presents a compliance emulator system as a new concept of tactile reproduction simulator which uses magnetic levitation in order to minimize friction and emulates compliance only along the vertical direction. Compliance is one of the important mechanical properties of the object related to tactile sensing of the human. The implemented system equipped with an analog LVDT sensor for a position sensor and employs a PD control with gravity compensation to emulate the specified compliance. To compensate the limited range of the system, the method of attaching the spring with various magnitude of stiffness to the system is adopted and its preliminary test is performed to confirm the validity of the method.

The Nelder-Mead simplex algorithm has become on of the most widely used methods for nonlinear unconstrained optimization, since 1965. Recently, this algorithm has been reevaluated and many papers on this algorithm are being published. The MATLAB computer software, highly renown in engineering, also provides the Nelder-Mead algorithm and the Denis-Woods modification with FMINS function. The authors made C++ code of these algorithms and compared with FMINS on the convergence behavior and the exactness of solutions. It shows that MATLAB's FMINS is inferior to author's C++ code. So, FMINS should be corrected for every user.

The determination of the design flood based on probabilistic concepts is one of the important matters of the general field of hydrology. Until now, Most of any existing formulas to predict the flood flow were estimated by very different values with each other when we applied these formulas to the small basin, in extreme case, which were estimated over top be 400% of a difference because these have been developed by foreigners or derived from the big basin. The objective of this thesis is to examine closely the characteristics of frequency flood flow for reliable prediction of the flood flow through the probabilistic method in hydrology and to develop the ($Q_T=27.74T^{0.178}A^{0.594}$) applicable to the river of Kangwon province.

The purpose of this study is to investigate the applicability of Nakayasu & SCS method and Clark method to the computation of runoff from the river basin in Soyang watershed. As the result, each runoff was conducted to compare and analyze existing established peak flow model, and to propose a pertinent model.

The numerical model predicting the behaviours of submerged mound constructed by dredged material is developed in this paper. The model is based on the Bailard's sediment transport formula, Stokes' second-order wave theory and the sediment balance equation. Nonlinear partial differential equation which is the same form as convection-dispersion equation which represents change of bed section can be obtained by substituting sediment transport equation for equation of sediment conservation. By this process, the analytical solution by which the characteristic of the behaviours of submerged mound can be estimated is derived by probably combining the convention coefficient and the dispersion coefficient governing the behaviours of submerged mound and the probability density function representing the wave characteristics. The validity of the analytical solution is verified by comparing the analytical solution which is assumed to estimate the movement rate submerged mound by bed-load with the field data of the past and its characteristic is analyzed quantitatively by obtaining the mean of the dispersion coefficient representing the extent of the decrease rate of the submerged mound height.

An efficient method is developed for classifying fingerprint data based on 2-D discrete wavelet transform. Fingerprint data is first converted to a binary image. Then a multi-level 2-D wavelet transform is performed. Vertical and horizontal subbands of the transformed data show typical energy distribution patterns relevant to the fingerprint categories. The proposed method with moderate level of wavelet transform is successful in classifying fingerprints into 5 different types. Finer classification is possible by higher frequency subbands and closer analysis of energy distribution.

Chemical oxidation of humic acid by ozonation process was investigated in the batch reactor. Aldehydes and ketone were identified as PFBOA derivatives in ozonated humic acid solutions using gas chromatography with PDECD. The formaldehyde was as a main by-product of ozonation. The characteristics of the formaldehyde production were discussed with respect to concentration at different experimental conditions.

In this paper, a 2D X-Y table, two axes of which are symmetrical, and a force sensing device are constructed, which comprise a 2D haptic interfacing apparatus. Two DC motors are used for actuating the two axes of the table and two precision encoders for sensing the position of each axis. Four PZTs are used for sensing the direction and the magnitude of the 2D force applied to the force sensing device by the user. The performance of the 2D haptic interface device is tested by 2D virtual object recognition experiments.

In this paper, We propose a new flow control scheme based on Queue Dynamics and it's Estimate Information in order to achieve higher throughput and network efficiency using control of the best-effort traffic. The feedback Information gives a result that compare queue length with queue threshold. Traffic changes at the time when queue length is cross over under the queue thresholds. The performance of the purposed scheme has been analyzed mathematically and we verify efficiency of the proposed method by means of simulation.