Low cycle fatigue life of spheroidal graphite cast iron is determined by the morphological parameters of internal graphite. The aim of this study is to clarify the effect of the number of nodular grain of spheroidal graphite cast iron on low cycle fatigue life. Two specimens that have identical average nodular grain size by changing nodular grain volume fraction and different number of nodular grain count was tested. In this paper, the parameter governing fatigue life through fatigue test, the number of nodular grain seriously affect fatigue life and nodular grain size is no longer governing parameter of it.

Sound insulation performance is investigated on the corrugated panel used for a rail way vehicle. Random incidence sound transmission loss is calculated by using the equivalent orthotropic plate model. Analysis results on several kinds of corrugated panels are in good agreement with the measured data. The analysis method is applied to predict the sound transmission loss of the corrugated panel used for Korean high speed train.

High pressure, pressure ratio, refrigerating effect, heat transfer from the condenser and the power of the compressor etc. of a self-made refrigeration equipment for R-12 are investigated when R-12 and R-134a are used as the coolants. The comparison between the performance for R-12 and that for R-134a is made. As a result, R-134a is better than R-12 in the view of high pressure, refrigerating effect and the coefficient of performance and vice versa in the view of pressure ratio, exit gas temperature from the compressor and heat transfer from the condenser.

Heat loss, fin effectiveness and efficiency of a plate fin are investigated as a function of non-dimensional fin length and Biot number using a two-dimensional separation of variables method. The value of temperature of the left side is set to be different from that of the right side for this plate fin to satisfy the real physical condition. Also temperature distribution within this plate fin is listed. One of the results shows that the fin can be considered to be useful in view of fin effectiveness on the given range of Biot number when non-dimensional fin length is larger than 3.

The definition of flatness is given by ISO, ANSI, KS, etc. but those standards don't mention about the specific methods for the flatness. So various solution models that are based on the Minimum Zone Method have been proposed as an optimization problem for the minimax curve fitting. But it has been rare to compare some optimization algorithms to make a guideline for choosing better algorithms in this field. Hence this paper examined and compared Genetic Algorithm and Simplex Method to the evaluation of flatness. As a result, Genetic Algorithm gave the better or equal flatness than Simplex Method but it has the inefficiency caused from the large number of iteration. Therefore, in the future, another researches about alternative algorithms including Hybrid Genetic Algorithm should be achieved to improve the efficiency of Genetic Algorithm for the evaluation of flatness.

Time Delay Control (TDC) method was proposed as a promising technique in the robust control area, where the plants have unknown dynamics with parameter variations and substantial disturbances are present. In this paper, based on the concepts of TDC, author propose a model reference control method for input/output model. The stability and robustness of the closed system has been analyzed for a class of linear time invarient (LTI) system. Then, in a simulation study, author's design method has been applied to a second order system, the result of which confirmed that the proposed control method performs satisfactorily as predicted.

A numerical study is done on the thrust vector control using gaseous secondary injection in the rocket nozzle. A commercial code, PHOENICS, is used to simulate the rocket nozzle flow. A $45^{\circ}-15^{\circ}$ conical nozzle is adopted to do numerical experiments. The flow in a rocket nozzle is assumed a steady, compressible, viscous flow. The exhaust gas of the rocket motor is used as an injectant to control the thrust vector of rocket at the constant rate of secondary injection flow. The injection location which is on the wall of rocket is chosen as a primary numerical variable. Computational results say that if the injection position is too close to nozzle throat, the reflected shock occurs. On the other hand, the more mass flow rate of injection is needed to get enough side thrust when the injection position is moved too far from the throat.

The purpose of this research is to find out how the inlet angle of secondary air affects the formation of recirculation zone inside a small incinerator. A commercial code, PHOENICS, is used to simulate the flow field of an incinerator. The computational grid system is constructed by Multi-Block technique. Numerical experiments are done with the five different angles of secondary air inlet. The formation of recirculation zone is evaluated by checking velocity fields. The computational results show that recirculation zone is clearly formed from 60 degree of inlet angle and the zone of recirculation is widen as angle of recirculation is increased to $75^{\circ}$.

One aims to find out how the operation condition of secondary inlet angle effects the temperature distribution inside a small incinerator. A finite volume commercial code, PHONICS, is used to simulate the temperature field in an incinerator. The computational grid system is constructed by Multi-Block technique. The governing equations based on the curvilinear coordinates are used. Numerical experiments are done with the five variations of secondary air inlet. The temperature distribution is quantified by the statistical deviation of temperature in an incinerator. The computational analysis says that the certain angle of secondary air inlet could improve the uniformity of temperature distribution in an incinerator.

A numerical investigation was performed to determine the effect of the Gurney flap on NACA 0015 airfoil. A Navier-Stokes code. FLUENT, was used to calculate the flow field about the airfoil. The fully-turbulent results were obtained using the standard ${\kappa}-{\varepsilon}$ two-equation turbulence model. The numerical solutions showed the Gurney flap increased both lift and drag. These results suggested that the Gurney flap served to increase the effective camber of the airfoil. Gurney flap provided a significant increase in lift-to-drag ratio relatively at low angle of attack and for high lift coefficient. It turned out that 0.75% chord size of flap was best. The numerical results exhibited detailed flow structures at the trailing edge and provided a possible explanation for the increased aerodynamic performance.

In order to observe the pattern forming of copper plate and chemical corrosion reaction, a study on the effect of the process parameters on the formation of micro-pattern by a photochemical etching of copper plate was carried out. The results are as follows : 1) Etching rate increases as the concentration of etchant increases under the regular condition of the temperature by the increasing of diffusion rate to surface. 2) Etching rate increases as the temperature of etchant increases by the fast acting of the material delivery of diffusion to surface under the regular condition of concentration. 3) It was found that etching speed increases as the material delivery of convection rising increased when the aeration speed of etchant increases. This result was from the fact acted by the material delivery of convection rising rather than material delivery of diffusion to the surface.

A study has been made on the behavior of microscopic fatigue crack growth at the stress level of the fatigue limit with ferrite-martensitic structures. For the above purpose, two types of the microstructures were prepared ; one is the microstructure having the ferrite encapsulating the islands of second phase martensite(FEM), the other is the microstructure with the martensite encapsulating the islands of ferrite(MEF). It has been pointed out that the fatigue limits of these microstructures are related to the critical stress at which the microcrack in the ferrite proceeds to the martensite. The high fatigue limit might be excepted for the MEF microstructure in which the critical crack length would be restricted within the second phase spacing in contrast with the FEM microstruture. However, the fatigue tests shows that no appreciable difference of the fatigue limits among them were recognized. Also, it turned out from the metallographic observations that the micro crack path is very much affected by the microstructures, so that the microcracks grow according to the 3-dimentional situation of its microstructures.

A model trains must have similitude with its original model not only in shape but also in motion. Motion characteristics of a model train under considerations are maximum velocity in straight and circular tracks and stopping distance. Equations of motions are derived to obtain maximum speed and stopping distance based on the Newton's Second Law and the energy principal. To accurately predict traction and resistance force between wheel and rail. wheel slip, or creepage, is taken into consideration. To verify the equations of motion, various experiments have been carried out including measurement of gear efficiency, location of mass center, rolling resistance force, traction force, slip, maximum velocity and stopping distance. This paper addresses how the experiments are setup and carried out in detail. Also the results of experiments are compared with the analytical prediction, which showed good agreements with each other.

Air springs are now widely used in bus or truck suspensions due to their advantages over conventional metal spring as coil or leaf springs. Air springs have soft spring rates, which give better ride quality, and additional leveling system provides constant ride height and maintains almost same vertical natural frequencies. A mathematical model of an air spring suspension system with height control system is constructed and dynamic responses of the suspension system are investigated in the light of leveling valve motion characteristic, vertical motion natural frequency. Also, using a full vehicle model, handling characteristics of an air spring suspension is studied and the results are compared with real test results, which shows good agreements.

There are many optimal design packages, but they are big ones and they have only a few kinds of optimal algorithm coded with Fortran and it is sometimes necessary for user to write down some codes into their packages. So it is hard for user to learn how to use and customize them. More over, there are no commercial home-made software for optimum design. So, in this paper, several famous optimum algorithms are coded and modulized with C++ which is known as a suitable computer language in order to build up more algorithms into one computer software. All algorithms developed with C++ here were tested for comparison with optimization tool box of MATLAB and are superior to MATLAB.

Heat dissipation technology using flow resonant phenomenon is a kind of new concept in heat transfer area. A vibration exciter is needed to generate air turbulence which has the natural shedding frequency of heat system. A mechanical vibrating device for the air flow oscillation is introduced, which is driven by a moving coil actuator. An analytical dynamic model for this mechanical vibration exciter is presented and its validity is verified by the comparison with experimental data. Values of some unknown system parameters in the analytic model are estimated through the system identification approach. Based on this mathematical model, a high bandwidth vibration phase, it turns out the high modal resonant characteristics of vibrating plate are the major barrier against obtaining a high bandwidth vibration exciter.

In this paper, we would like to develop the bending collapse specific equation of aluminum members which are usually used in light-weight vehicle or electromobiles. The result of the developed equation are compared with that of test and finite element methods as the moment-rotational angle curves. Three types of aluminum members are tested with the pure bending collapse test rig. PAM-CRASH and ABAQUS program are used for finite element analysis. As the result the developed bending collapse governing equation is accurate in estimating the yield moment and the maximum moment. Especially, in the case of the local buckling and the delayed buckling, the developed equation is better effective than F.E.M.

To support Quality of Service (QoS) in the existing Internet, Differentiated Service (Diff-Serv) has been proposed. But, the unfairness between TCP connections remains as a serious problem not only in the conventional best-effort service Internet but also in new Diff-Serv network. In this paper, we propose the Balancing Marker Algorithm (BMA) improving the fairness between individual connections of aggregated sources in a Diff-Serv network. This algorithm is based on the 3-level priority marking method. We compared the 2-level packet priority marker with the Balancing Marker proposed in this paper. And we showed that the BMA improved the fairness and the throughputs between the individual connections with different delays in an aggregated source.

This paper proposes an overmodulation strategy for space-vector PWM(SVPWM). The overmodulation strategy increases a fundamental output voltage and improves a voltage utilization up to the maximum in the overmodulation region. To maintain a linearity of the relation between a reference voltage and a fundamental output voltage, this paper suggests a compensation voltage, whose magnitude or phase is modified to the proposed control scheme. The practical implementation is simple and it is applied to improve an output voltage of SVPWM controlled AC Motor in the steady-state. The characteristic of the proposed strategy is confirmed by simulations and experiments for a V/F control of a induction motor.

Although Fuzzy Logic Controller(FLC) adopted three terms as input gives better performance, FLC is in general composed of two-term control because of the difficulty in the construction of fuzzy rule base. In this paper, a three-term FLC which is similar to PID control but acts as a nonlinear controller is proposed. To reduce the complexity of the rule base design and to increase efficiency. a simplified fuzzy PID control is induced from a hybrid velocity/position type PID algorithm by sharing a common rule base for both fuzzy PI and fuzzy PD parts. It is simple in structure, easy in implementation, and fast in calculation. The phase plane technique is applied to obtain the rule base for fuzzy two-term control and the resultant rule base is Macvicar-Whelan type. And the membership function is a Gaussian function. The frequency response information is used in tuning of the membership functions. Also a tuning strategy for the scaling factors is proposed based on the relationship between PID gain and the scaling factors. Simulation results show better performance and the effectiveness of the proposed method.

This paper gives a fundamental study of the design method of Flyback Transformer(FBT) in the Multioutput Flyback DC-DC Converter. We explained a winding strategy and Core selecting of the Flyback transformer to get the design guidelines for optimizing the performance of Flyback DC-DC Converter. The final goal of this paper is to obtain design rules of the Flyback transformer to minimize the leakage inductance for good quality of DC Souce.

The most of metalhalide lamps is what the momentary restarting cannot be realized when the arc tube is in the hot condition. The discharge starting voltage of arc tube in the hot condition is much higher than in the cold condition in proportion to the gaseous pressure. Therefore it takes about ten minutes to restart the metal Halide lamps, that is to say, it is possible to start when the pressure and the temperature are decreased. But, if the lamp is restarted in the hot condition, we must supply the high voltage pulse with 15kV between the both electrodes of lamp. The proposed ignitor has two ignitors. If we connect each ignitor at the both sides, the high voltages of two different frequencies are generated. If so, when the one of the ignitor generates the highest voltage and the other applied to elecrodes of the lamp. In this way, we can restart the lamp with the voltage 15kV, even if the lamp is in the hot condition.

In this paper, a novel speed control strategy using an acceleration feedforward compensation by the estimation of the system inertia is proposed. With the proposed method, the enhanced speed control performance can be achieved and the speed response against the disturbance torque can be improved for the vector-controller induction motor drive systems in which the bandwidth of the speed controller cannot be made large enough. The experimental results confirm the validity of the proposed strategy.

In this paper, we present a development of automatic fog water collector that operates during fog events. This collector consists of fraction collectors, a wind hall and a fog sensor. When a fog event is begin, then the fog sensor would judge whether it is a fog or not. If a fog is detected, the fog would be gathered by air suction fans, At the same time, the wind direction, the wind velocity, the atmospheric temperature and pressure would be measured and record simultaneously. We are also developing a wireless communication system for the remote control and data analysis to collect, store and process data collected in the automatic fog water collector.

In this paper, we present a BLDC Motor control for needle positioning and velocity control in the industrial sewing machine. In the industrial sewing machine, the fast acceleration control is needed, especially for a person who has a skill in operation of sewing machine for more products. And it is also needed to have a less noise and vibration. But the system which is made in a low price has no feedback system for a current control. Therefore we propose the method of velocity pattern that has an acceleration of velocity and Anti-windup algorithm. By the experiment, we confirmed that these manner have a good performance for low noise, low vibration and fast acceleration in the industrial sewing machine.

This paper describes the path planning method in an unknown environment for an autonomous mobile robot equipped with CCD(Charge-Coupled Device) camera. The mobile robot moves along the guideline. The CCD camera is used for the detection of the existence of a guideline. The wavelet transform is used to find the edge of guideline. It is possible for us to do image processing more easily and rapidly by using wavelet transform. We make a fuzzy control rule using image data as an input then determined the position and the navigation of the mobile robot. The center value of guideline is the input of fuzzy logic controller and the steering angle of the mobile robot is the fuzzy controller output. Some actual experiments show that the mobile robot effectively moves to target position by means of the applied fuzzy control.

A priori information of object is needed to control in some well known control methods. But we can't always know a priori information of object in real world. In this paper, the inverted pendulum is simulated as a control task with the goal of learning to balance the pendulum with no a priori information using neural network controller. In contrast to other applications of neural networks to the inverted pendulum task, the performance feedback is unavailable on each training step, appearing only as a failure signal when the pendulum falls or reaches the bound of track. To solve this task, the delayed performance evaluation and the learning of nonlinear of nonlinear functions must be dealt. Reinforcement learning method is used for those issues.

For efficient massive image retrieval, an image retrieval requires that several important objectives are satisfied, namely: automated extraction of features, efficient indexing and effective retrieval. In this work, we present a technique for extracting the 4-dimension directional feature. By directional detail, we imply strong directional activity in the horizontal, vertical and diagonal direction present in region of the image texture. This directional information also present smoothness of region. The 4-dimension feature is only indexed in the 4-D space so that complex high-dimensional indexing can be avoided.

The nearest neighbor query is an important operation widely used in multimedia databases for finding the object that is most similar to a given query object. Most of techniques for processing nearest neighbor queries employ multidimensional indexes for effective indexing of objects. However, the performance of previous multidimensional indexes, which use N-dimensional rectangles or spheres for representing the capsule of the object cluster, deteriorates seriously as the number of dimensions gets higher. This paper proposes a new index structure based singular value decomposition resolving this problem and the query processing method using it. We also verify the superiority of our approach through performance evaluation by performing extensive experiments.

In this paper, we propose a new novel method for similarity search that supports time warping. Our primary goal is to innovate on search performance in large databases without false dismissal. To attain this goal, we devise a new distance function $D_{tw-lb}$ that consistently underestimates the time warping distance and also satisfies the triangular inequality. $D_{tw-lb}$ uses a 4-tuple feature vector extracted from each sequence and is invariant to time warping. For efficient processing, we employ a multidimensional index that uses the 4-tuple feature vector as indexing attributes and $D_{tw-lb}$ as a distance function. We prove that our method does not incur false dismissal. To verify the superiority of our method, we perform extensive experiments. The results reveal that our method achieves significant speedup up to 43 times with real-world S&P 500 stock data.

ISDN AO/DI provides efficient communication. It dynamically allocates channels for bandwidth, which is key component for packet data communication. In this paper, we analyze performance improvement of ISDN AO/DI system with buffering scheme and compare with AO/DI system without buffering scheme. From the simulation of AO/DI with buffering scheme, we see that the required bandwidth is less than of the AO/DI system without buffering scheme.

The study of game traffic has neglected by scientists, but as Internet gaming becomes more popular, multiplayer online games have become a significant element of Internet traffic. In this paper we analyze Internet traffic generated by sessions of multiplayer online games and study source models of multiplayer online game traffic. Our analysis shows that the empirical game traffic can be characterized by certain analytical model. We describe how our empirical traffic data set can be modeled and discuss how game server type influences interarrival distribution.