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Over dependence on energy sources of fossil fuel origin to meet the ever-increasing global energy demand not only leads to depletion of nonrenewable energy sources but also results in greenhouse gas emission mediated climatic crisis. Therefore, the renewed research interests in the quest of alternate sources of sustainable and clean energy research are being prioritized in recent times. Microbial electrochemical systems (MESs) are engineered electrochemical systems that facilitate the direct transformation for organic wastes into bioenergy through microbial catalyzed reactions. MESs hold great potential as green bioenergy conversion technologies and related laboratory-scale research have reached unprecedented success in the past 5–10 years. Despite the advantages of this technology, the widespread commercial application of the technology was restrained by limitations of slow microbial kinetics, low efficiency, and high cost. In the last few years, significant advancements have been attempted in the reactor configurations, electrode materials, substrate types, diversity of electrogenic microorganisms, etc., thereby increasing the performance efficiency to several folds. However, further improvements are highly desired for the MESs to be economically viable. This chapter offers an inclusive review of all the recent developments that have been made in MESs emphasizing on bioenergy perspective. In particular, it highlights novel anodes, bio-cathodes, engineered microbes, and xenobiotics of diverse classes that can be exploited for bioenergy production. Besides that, this chapter discusses the scale-up and practical implementation in large-scale settings as pioneering attempts of commercialization.

Outrigger systems, which consist of a core wall, external columns, and outriggers, are widely used in structural systems in high-rise buildings to control lateral displacements. This study proposes an optimal design method for minimizing the volume of the primary structural members (core wall, outrigger, and external columns) and calculating the optimal locations of outriggers using a genetic algorithm with the goal of efficiently controlling the lateral displacement of a high-rise building. The optimal solution of the outrigger system was determined based on the change in the number of stories (from one to four) at which outriggers were installed in a prototype model (a 400-m high-rise building). The results indicate that increasing the number of outrigger installations reduces the total volume of structural members needed in the outrigger system to satisfy the displacement constraint of the top floor (H/500, H: building height). Additionally, the cross-sections of the core wall and outrigger decreased and that of the external column increased, which indicated that the role of the external column in the control of lateral displacements increased as the number of outrigger installations increased. As a result, the contribution of the core wall to the bending moment decreased, which reduced the cross-section of the core wall. These results provide an optimal solution that considers the ideal locations of the outriggers and minimizes the volume of structural members within the maximum lateral displacement range, which is specified as a structural performance constraint. Therefore, this study can provide designers with a well-defined target performance level (e.g., lateral displacement or bending stress) during the initial stage of the outrigger system design process and an economical design that minimizes cost.

Tester Interface Software (TIS) provides all software functions that are necessary for a testing device to perform the test process on a memory semiconductor package from the time the device is put into the test equipment until the device is discharged from the equipment. TIS should perform the same work over all types of equipment regardless of their tester models. However, TIS has been developed and managed independently of the tester models because there are various equipment and computer models that are used in the test process. Therefore, more maintenance, time and cost are required for development, which adversely affects the quality of the software, and the problem becomes more serious when the new tester model is introduced. In this paper, we propose the Cross-platform Tester Interface Software (CTIS) framework, which can be integrated and operated on heterogeneous equipment and OSs.

Recent days, real-time 3D visualization is widely required for pervasive games. Despite the use of level-of-detail techniques, the real-time rendering of massive terrain datasets exceeds the capability of today's graphics hardware. So, to visualize the realistic terrain on various devices, the oversimplification of datasets is required. The oversimplification reduces computing and data transmission time. Owing to the oversimplification, however, artifacts such as geo-popping may appear in rugged regions, particularly when low level-of-detail is involved. Geo-popping is undesirable visual effect that occurs when the transition of a 3D object to a different level of detail is performed. To reduce such artifacts, we propose a novel mesh simplification method by concentrating on the vertices of regular grids in a rugged area using the concept of attraction and elastic forces. Each sampling point of the terrain data may pull on adjacent vertices with an attraction force that corresponds to its predicted surface roughness. However, strong attraction forces may cause a geometrical twisting or overlapping problems. To solve these problems, we apply an elastic force to a vertex and its neighbors. This makes each vertex push its neighbors away when they are too close. Computing the displacement of each vertex using attraction and elastic forces provides a fine-mesh terrain representation in rough areas, and a coarse-mesh representation in smooth areas. As a result, our method efficiently visualizes more accurate terrain scenes by reducing the number of geo-popping that mainly appear in rugged areas.

[EN] We propose the automatic generation of the ortho-photo data which support realistic scenes for DEM by texture mapping. This ortho-photo data is automatically generated by pattern recognition techniques using Bayesian classifier which uses the features extracted from a DEM and its geo-referenced ortho-photo data as training sets. We defined the various features of each texel such as its height, slope angle, slope direction, surface curvature, hue, saturation and brightness from the training datasets. The proposed method makes possible for mapping texture of a realistic ortho-photo data to virtual terrain data which are unable to take satellite photo or aerial photo. These case are often in of computer game and digital movie area. Also, generating ortho-photo with the enlarged DEM, it does not cause the aliasing from the difference of resolution. It makes very similar images with real photography by shading and efficiently handles ortho-photo data and elevation data occupied enormous storage in cloud computing environment., This work was supported by INHA UNIVERSITY Research Grant.

We cannot load the entire data for high-resolution terrain model to the GPU memory since its size is too big. Out-of-core approaches are commonly used to solve the problem. However, due to limited bandwidth of the secondary storage, it is difficult to render the terrain in real-time. A method that compresses the DEM data with wavelet transform on GPU, and renders the decoded data is suggested. However, it is inefficient since it has to sample the values from textures, convert them to vertices, and generate a mesh periodically. We propose a method to store the approximation coefficients of wavelet compression as vertex attributes and render the terrain by decoding the data on geometric shader. It can reduce the amount of transferring terrain texture since approximation coefficients are given as an attribute of the vertex. Also, it generate meshes without additional upload of terrain texture.Keywords : Terrain rendering(지형렌더링), Real-time rendering(실시간렌더링), Wavelet (웨이블릿), Level of Detail(상세단계)

The number of mountain climbers increases as leisure time expands and the awareness of public health is promoted. However, thanks to physiographic features and carelessness of mountain climbers, the rate of accidents on the mountains also increases. When urgent accidents occur on the mountains, helicopters are usually used for the emergencies adjusting to the difficult access. The objective of this study is to analyze the spots for helicopter to land and take off when accidents occur on the mountains by using GPS to support decision-making for emergency saving system. The target area for this study was limited to Pucheon, Gyeonggi-do, in Korea. The spots for saving were classified into two such as landing spots and take-off spots for helicopter to respond to the emergencies on the practical site. Digital map, forest type map, and forest soils map were used as fundamental data. This study was performed excluding factors such as direction of the wind, speed of the wind, etc. In the future, associated with DB from the Meteorological Administration, more efficient analysis will be required.

Since large terrain data can not be loaded on the GPU or CPU memory at once, out-of-core methods which read necessary part from the secondary storage such as a hard disk are commonly used. However, long delay may occur due to limited bandwidth while loading the data from the hard disk to memory. We propose efficient rendering method of large terrain data, which compresses the data with wavelet technique and save its coefficients in RGBA channel of an image us, then decompresses that in rendering stage. Entire process is performed in GPU using Direct Compute. By reducing the amount of data transfer, performing wavelet computations in parallel and doing decompression quickly on the GPU, our method can reduce rendering time effectively.

The asymmetric vortex regime of a von Karman ogive with fineness ratio of 3.5 is experimentally studied at a Reynolds number of 156,000. Both port and starboard plasma actuators are used to introduce fluidic disturbances at the tip of the ogive which are amplified through the flow's convective instability and produce a deterministic port or starboard asymmetric vortex state (i.e. side force). Accurate control or manipulation of this asymmetric vortex state holds the potential for increased maneuverability and stability characteristics of slender flight vehicles at high angle of attack. Open-loop experimental tests are used to understand and quantify the vortex dynamics due to actuation inputs. Linear time invariant models provide a suitable model structure to replicate the vortex dynamics and allow for simulation and closed-loop control design. Standard PID control is designed and implemented. A closed-loop simulation shows arbitrary side force tracking with adequate disturbance rejection.

An ARX(Auto-Regressive eXogenous) modeling technique for vortex dynamics in the BFS(Backward Facing Step) flow field is proposed in this paper. In order for the modeling of the dynamics, the spatial and temporal modes are extracted through POD(Proper Orthogonal Decomposition) analysis. Determining the orders of the inputs and outputs for an ARX structure is carried out by the spectrum analysis and temporal mode analysis, respectively. The order of input delay terms is also determined by the flow velocity. Finally the coefficients of the ARX model are designed by using an artificial neural network.

Recent terrain rendering applications such as 3D games and virtual reality, use GPU-based ray-casting method for rendering high-quality scenes in realtime. As the size of terrain dataset grows bigger, the rendering speed will be decreased by the increase of the number of texture samplings. To accelerate the conventional ray-casting, we propose an efficient ray casting method with subdivided bounding boxes which are based-on GPU quadtree traversal. The subdivision of the terrain's bounding box can reduce the empty spaces effectively. By performing the ray-casting with this compact bounding box, we can efficiently reduce computation with empty space skipping. Unlike the recent quadtree-based empty space skipping techniques which perform the tree traversal at each ray, our method traverses the tree only once per frame. Therefore, we can save much computational time.

Recent results of corpus-based linguistics demonstrate that context-appropriate sentences can be generated by a stochastic constraint satisfaction process. Exploiting the similarity of constraint satisfaction and DNA self-assembly, we explore a DNA assembly model of sentence generation. The words and phrases in a language corpus are encoded as DNA molecules to build a language model of the corpus. Given a seed word, the new sentences are constructed by a parallel DNA assembly process based on the probability distribution of the word and phrase molecules. Here, we present our DNA code word design and report on successful demonstration of their feasibility in wet DNA experiments of a small scale.

Recently in terrain rendeing, most researches introduce mipmap-based out-of-core methods for handling large sized DEM data which does not fit in main memory of general computer. However, mipmap-based LOD(level-of-detail) methods occur geometric errors which appear in data simplifying the higher LOD level. These geometric errors cause geometric popping effects where LOD level changes when viewpoint moves. In this paper, we propose vertex cohesion map for reducing geometric error. In preprocessing step, we generate vertex cohesion map, which is a texture that stores the vectors. By these vectors, each vertex will be cohered into the position in which the difference of gradient value is bigger than others. Therefore in terrain rendering, using vertex cohesion map can dramatically reduce the geometry popping effects rather than using mipmap.

A turbine stage consists of stators and rotors. The stator provides the required inlet flow conditions so that the rotor can produce the necessary power. Passing wakes generated from the trailing edge of the stator make an interaction with the rotor. In the present study, this flow mechanism is investigated using the numerical analysis. In case of a large gap distance between the stator and rotor, the flow can be solved independently. First, only the stator flow field is solved. Second, the rotor flow field is solved including the passing wake characteristics obtained from the stator analysis. The passing wake experiences the shearing as it approaches to the rotor blade leading edge. And it is chopped when it strikes the rotor blade. After that, the chopped wakes becomes the prolongation as it travels downstream. The flow according to the variation of the gap distance is also studied. Pressure jumps due to the passing wakes result in the pressure and lift loss and it gets stronger with the closer gap distance.

An impulse turbine, which is a main component of a liquid rocket engine, needs to be a small size with light weight and generate large power. Since the impulse turbine is being operated under complicated supersonic conditions, flow analysis and performance prediction largely depend on CFD technique. In order to increase the reliability of the prediction code, however, it often requires an experimental data to compare. In this research a rotating turbine rotor with multiple blades is simulated with a two-dimensional stationary cascade to check the effect of major flow parameters. Mach number is measured at nozzle exit by using a pitot tube and the blade thrust was also measured with a load cell. The measured thrust coefficient and the power are compared well with the designed conditions, which proves the design procedures are properly taken.

Four design candidates for a partial admission turbine have been chosen from a preliminary design process. Their performance were estimated through the 3-D numerical analyses using a frozen rotor method. In order to select the optimum design, each flow analysis result was compared with others. Flow characteristics in the passages and some types of losses induced by shocks and wakes were found from calculation results. Based on these calculations, a new rotor blade was redesigned and compared with previous one through flow analysis.

To verify the changes of mesopic and photopic contrast sensitivity function of sound eye whose visual acuity was kept the same after occlusion therapy in the amblyopic children. Fourteen sound eyes of amblyopic children (mean; 7.67 years; S.D., 1.50 years) who kept their visual acuity the same after the occlusion therapy were tested. The children had 6 hours of part-time patch therapy for 3 months prior to this examination. Among 14 amblyopic children, 8 were anisometric and 6 were strabismic amblyopes. Using the visual capacity analyzer which measures the minimal contrast level at from low to high spatial frequencies, the contrast sensitivity of sound eye was measured, under both photopic and mesopic condition, before and after 3 months of occlusion therapy. Comparing the contrast sensitivity of sound eye after the occlusion therapy to that before the occlusion, there was no statistical difference in photopic condition. When it comes to mesopic condition, the contrast sensitivity decreased at the intermediate spatial frequency level (3-13 c.p.d, p=0.028) after the occlusion therapy. The occlusion caused statistically significant decrease in mesopic contrast sensitivity, when the visual acuity was not changed after the occlusion therapy. It may indicate that mesopic contrast sensitivity can be considered as a useful tool for early detection of hidden occlusion amblyopia.

In this paper, a small supersonic wind tunnel was designed and built to study the flow characteristics of a supersonic impulse turbine cascade by experiment. The flow was visualized by means of a single pass Schlieren system. The supersonic cascade with 3-dimensional supersonic nozzle was tested over a wide range of pressure ratio. Highly complicated flow patterns including shocks. nozzle-cascade interaction and shock boundary layer interactions were observed.

The turbine efficiency is an important factor in power plant, and accurate evaluation of steam turbine performance is the key issue in turbo machinery industry. The difficulty of evaluating the steam turbine performance due to its high steam temperature and pressure environment makes the most steam turbine tests to be replaced by air similarity test. This paper presents how to decide the similarity conditions of the steam turbine test and describes its limitations and assumptions. The test facility was developed and arranged to conduct an air similarity turbine performance test with various inlet pressure, temperature and mass flow rate. The eddy-current type dynamometer measures the turbine-generated shaft power and controls the rotating speed. Pressure ratio of turbine can be controled by back pressure control valve. To verify its test results, uncertainty analysis was performed and relative uncertainty of turbine efficiency was obtained.

The KSR-3 magnetometers consist of the fluxgate magnetometer (MAG/AIM) for acquiring the rocket flight attitude information, and the search-coil magnetometer (MAG/SIM) for the observation of the Earth's magnetic fluctuations. The position (latitude, longitude, and height) and flight condition (the transformation angle) of the rocket is measured after the data based on these two magnetometers are compared with IGRF. The gap in the vector of magnetic field between the position of the launching point and an impact point is taken into account in data reduction. Angular variation of pitch, yaw, and roll can be researched when the data is applied to the coordinate system of the rocket.

There are many methods to enhance the fault tolerance of the CORBA based real time systems by viewpoints. Among them, this paper provides a method to enable seamless services where the systems based on the CORBA have object`s faults originated processing real time information. Namely, this paper observes a method to deal efficiently with object`s faults happening in 3 tier architecture environments. It is possible to replicate objects as a way to enhance the fault tolerance considering object`s faults. Along with it, this paper shows a method to enhance the fault tolerance ultimately and then keep the service continuity by prividing a way to allow to continue to run the systems until the FT-CORBA based one`s faults are recovered.

This paper describes the re-design and the calibration results of the MAG digital circuit onboard the KSR-3. We enhanced the sampling rate of magnetometer data. Also, we reduced noise and increased authoritativeness of data. We could confirm that AIM resolution was decreased less than 1nT of analog calibration by a digital calibration of magnetometer. Therefore, we used numerical-program to correct this problem. As a result, we could calculate correction and error of data. These corrections will be applied to magnetometer data after the launch of KSR-3.

Ultrasound volume rendering is an efficient method for visualizing the shape of fetuses in obstetrics and gynecology. However, in order to obtain high-quality ultrasound volume rendering, noise removal and coordinates conversion are essential prerequisites. Ultrasound data needs to undergo a noise filtering process; otherwise, artifacts and speckle noise cause quality degradation in the final images. Several two-dimensional (2D) noise filtering methods have been used to reduce this noise. However, these 2D filtering methods ignore relevant information in-between adjacent 2D-scanned images. Although three-dimensional (3D) noise filtering methods are used, they require more processing time than 2D-based methods. In addition, the sampling position in the ultrasonic volume rendering process has to be transformed between conical ultrasound coordinates and Cartesian coordinates. We propose a 3D-mipmap-based noise reduction method that uses graphics hardware, as a typical 3D mipmap requires less time to be generated and less storage capacity. In our method, we compare the density values of the corresponding points on consecutive mipmap levels and find the noise area using the difference in the density values. We also provide a noise detector for adaptively selecting the mipmap level using the difference of two mipmap levels. Our method can visualize 3D ultrasound data in real time with 3D noise filtering.

We propose adaptive power control of obstacle avoidance system for visually impaired person. It utilizes multiple ultrasonic sensors to avoid obstacles lying in the path. We evaluate complex structure in front of the user with predefined patterns and determine avoidance direction by analysing those patterns. It controls the number of active ultrasonic sensors by evaluating motion context using built-in accelerometer sensor. Our system safely guides visually impaired person as well as adaptively control power consumption of mobile devices.

Recent researches of terrain visualization require fast and accurate rendering of massive terrain datasets. GPU-based ray-casting algorithm is one of the terrain visualization methods which support artifact-free scenes with fast rendering speed. However, as the resolution of dataset and display device has been grown larger, acceleration techniques are required for rendering the terrain in real-time. In this paper, we propose an acceleration technique using vertex propagation, which accelerates the ray-casting with quadtree-based empty space skipping. We perform the vertex propagation by subdividing a bounding box of the terrain. These boxes produce an optimal boundary of terrain which depends on viewing conditions. By marching the ray/height-field intersection only inside the bounding boxes, we can efficiently skip empty spaces. Experimental results show our method efficiently reduced the number of repetitions in previous quadtree traversal techniques and decrease the rendering speed about 30–50%.

Purpose: The purpose of this study was to determine the significant factors for risk estimate of aspiration and to evaluate the efficiency of the dysphagia assessment tool. Methods: A consecutive series of 210 stroke patients with aspiration symptoms such as cough and dysphagia who had soft or regular diet without tube feeding were examined. The dysphagia assessment tool for aspiration was compared with videofluoroscopy using Classification and Regression Tree (CART) analysis. Results: In CART analysis, of 34 factors, the significant factors for estimating risk of aspiration were cough during swallowing, oral stasis, facial symmetry, salivary drooling, and cough after swallowing. The risk estimate error of the revised dysphagia assessment tool was 25.2%, equal to that of videofluoroscopy. Conclusion: The results indicate that the dysphagia assessment tool developed and examined in this study was potentially useful in the clinical field and the primary risk estimating factor was cough during swallowing. Oral stasis, facial symmetry, salivary drooling, cough after swallowing were other significant factors, and based on these results, the dysphagia assessment tool for aspiration was revised and complemented.

Unique starlike CdS particles were prepared from the lyotropic triblock copolymer solution system. The starlike CdS consists of a spherical core and dozens of the attached conical nanolobes. From the comparative studies with the spherical and rod-shaped CdS nanoparticles, the unique photophysical property is presented for the starlike CdS particle. The experimental results suggest that the photogenerated charge carriers at the tip-edge region of the conical nanolobe in the starlike CdS system diffuse into the thicker inner part including the core region, which is possibly due to the decreasing excited state potential gradient from the tip edge to the thicker inner part. This type of charge carrier diffusion dynamics from the surrounding to the thicker inner part in this anisotropic morphology of the starlike CdS semiconductor closely resembles the energy transfer dynamics in the organic dendrimers.

A prototype centrifugal compressor was designed for applying to a small turboshaft engine, and tested [1, 2]. As a component of the small turboshaft engine, the impeller has rather high value of inlet hub-tip ratio, 0.64. Also, for the compactness of engine, the compressor was designed with restricted dimensions in diameter. The absolute Mach number at the exit of the impeller reaches to sonic velocity to attain design pressure ratio, 4.89. Thus, the effective pressure recovery is the one of the main concern within the given dimension. The compressor in this study employs two-row tandem diffusers aiming high efficiencies. 3D viscous calculations are carried out to understand the flow structures in detail. Numerically predicted flow fields for off design conditions as well as for on design condition are discussed. Effects on the relative circumferential positions of the diffuser rows are studied for the cases of isolated diffusers to quantify the preferable configurations. According to the flow fields, it would be preferable to have some twist angles at leading edges for both rows of the diffusers to adapt incoming flows. On choking condition, recirculating flows are observed at the shroud region of the 2nd row diffuser.Copyright © 2003 by ASME