• The Journal of the Acoustical Society of Korea
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• v.28 no.3
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• pp.260-267
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• 2009

It is very difficult to form a desired complex sound field at a designated region precisely as an application of acoustic arrays, which is one of important objects of array systems. To solve the problem, a filter design method was suggested, which employed the concept of an inverse method using the acoustical holography based on the boundary element method. In the acoustical holography used for the source identification, the measured field data are employed to reconstruct the vibro-acoustic parameters on the source surface. In the analogous problem of source array design, the desired field data at some specific points in the sound field was set as constraints and the volume velocity at the surface points of the source plane became the source signal to satisfy the desired sound field. In the filter design, the constraints for the desired sound field are set, first. The array source and given space are modelled by the boundary elements. Then, the desired source parameters are inversely calculated in a way similar to the holographic source identification method. As a test example, a target field comprised of a quiet region and a plane wave propagation region was simultaneously realized by using the array with 16 loudspeakers.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.475-487
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• 2024

As today's "ninth art", role-playing games recognized by most players due to their surreal themes and sustained reflection on social diseases. Through precise control of story-telling and game visuals, players develop an avatar identification during role-playing game. Based on Lacan's mirror stage theory, a new self-identity mechanism is established under the guidance of role-playing games. As a "player", the subject's interpretation of himself is shifted by the game order, and the subject identifies with the role-playing game while at the same time being structured by the desire of role-playing game. The immersive experience and emotional guidance of role-playing games all point to the most instinctive human desires. The psychoanalytic theory from Lacan's perspective explains the source of players' desire, and the expression of players' desire in the game. It also plays an important role in the emotional rendering and identity aspects of role-playing games. This paper is to establish that role-playing games do have an impact on the player's self-identity through a Lacanian psychoanalytic reading of role-playing games.

• Geomechanics and Engineering
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• v.37 no.5
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• pp.475-498
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• 2024

The prediction of the susceptibility of soil to liquefaction using a limited set of parameters, particularly when dealing with highly unbalanced databases is a challenging problem. The current study focuses on different ensemble learning classification algorithms using highly unbalanced databases of results from in-situ tests; standard penetration test (SPT), shear wave velocity (V_s) test, and cone penetration test (CPT). The input parameters for these datasets consist of earthquake intensity parameters, strong ground motion parameters, and in-situ soil testing parameters. liquefaction index serving as the binary output parameter. After a rigorous comparison with existing literature, extreme gradient boosting (XGBoost), bagging, and random forest (RF) emerge as the most efficient models for liquefaction instance classification across different datasets. Notably, for SPT and V_s-based models, XGBoost exhibits superior performance, followed by Light gradient boosting machine (LightGBM) and Bagging, while for CPT-based models, Bagging ranks highest, followed by Gradient boosting and random forest, with CPT-based models demonstrating lower G_mean(error), rendering them preferable for soil liquefaction susceptibility prediction. Key parameters influencing model performance include internal friction angle of soil (ϕ) and percentage of fines less than 75 µ (F₇₅) for SPT and V_s data and normalized average cone tip resistance (q_c) and peak horizontal ground acceleration (a_max) for CPT data. It was also observed that the addition of V_s measurement to SPT data increased the efficiency of the prediction in comparison to only SPT data. Furthermore, to enhance usability, a graphical user interface (GUI) for seamless classification operations based on provided input parameters was proposed.

• Journal of fish pathology
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• v.37 no.1
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• pp.49-60
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• 2024

A viable but non-culturable (VBNC) state is a survival strategy adopted by bacteria when faced with unfavorable environmental conditions, rendering them unable to grow on nutrient agar while maintaining low metabolic activity. This study explored the impact of temperature and nutrient availability on inducing VBNC state in Edwardsiella piscicida, the most important bacterial fish pathogen, and assessed its pathogenicity at VBNC state. E. piscicida was suspended in filtered sterile seawater and exposed to three different temperatures (4, 10, and 25℃) to induce the VBNC state. Subsequently, the induced VBNC cells were subjected to resuscitation by either raising the temperature to 28℃ or inoculating them in brain heart infusion broth supplemented with 1% NaCl. A propidium monoazide (PMA)-qPCR method was also developed to selectively quantify live (VBNC or culturable) E. piscicida cells. The results showed that the bacteria entered the VBNC state after approximately 1 month at 4℃ and 25℃, and 2 months at 10℃. The VBNC E. piscicida cells were successfully revived within 3 days in a nutrient-rich environment at 28℃, highlighting the significance of temperature and nutrition in inducing and resuscitating the VBNC state. In pathogenicity tests, resuscitated E. piscicida cells exhibited high pathogenicity in olive flounder comparable to cultured bacteria, while VBNC cells showed no signs of infection, suggesting they are unlikely to resuscitate in fish. In conclusion, this study contributes to our understanding of fish pathogen ecology by investigating the characteristics of the VBNC state under varying temperature and nutrition conditions.

• Journal of the Korean Society of Safety
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• v.39 no.2
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• pp.38-43
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• 2024

Recently, with the expanding market for electronic devices and electric vehicles, secondary battery usage has been on the rise. Lithium-ion batteries are particularly popular due to their fast charging times and lightweight nature compared to other types of batteries. A secondary battery consists of four components: anode, cathode, electrolyte, and separator. Generally, the positive and negative electrode materials of secondary batteries are composed of an active material, a binder, and a conductive material. Acetylene Black (AB) is utilized to enhance conductivity between active material particles or metal dust collectors, preventing the binder from acting as an insulator. However, when recycling waste batteries that have been subject to high usage, there is a risk of fire and explosion accidents, as accurately identifying the characteristics of Acetylene Black dust proves to be challenging. In this study, the lower explosion limit for Acetylene Black dust with an average particle size of 0.042 ㎛ was determined to be 153.64 mg/L using a Hartmann-type dust explosion device. Notably, the dust did not explode at values below 168 mg, rendering the lower explosion limit calculation unfeasible. Analysis of explosion delay times with varying electrode gaps revealed the shortest delay time at 3 mm, with a noticeable increase in delay times for gaps of 4 mm or greater. The findings offer fundamental data for fire and explosion prevention measures in Acetylene Black waste recycling processes via a predictive model for lower explosion limits and ignition delay time.

• Journal of Ecology and Environment
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• v.48 no.2
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• pp.163-172
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• 2024

Background: Fruit bats are natural carriers of Nipah virus (NiV). The primary objective of this study is to identify potential reservoir species in a selected geographic regions. It is necessary to determine an accurate species identification of the associated reservoir bat species distributed in a specific region. Results: In this study, we collected 20 different bat specimens from the NiV-prone area of the Kushtia district. Among these, 14 were tissue samples (BT-1-14) and six were fecal samples (BF-1-6). We used the mitochondrial gene cytochrome b, one of the most abundant and frequently used genetic markers, for polymerase chain reaction amplification and sequencing. Out of the 20 samples, 12 tissue samples and 2 fecal samples were successfully amplified and sequenced. However, two tissue samples and four fecal samples yielded chimeric sequences, rendering them unsuitable for annotation. The sequences of the successfully amplified samples were compared to those deposited in the National Center for Biotechnology Information database using basic local alignment search tool to identify the bat specimen collected. The study identified six different bat species using both morphological and genetic data, which may carriers of the NiV. Conclusions: Our results suggest that additional research should be conducted to gather more information on fruit bats from different localities across the country. The study contributes to the establishment of appropriate measures for NiV carrying disease control and management.

• Journal of the Korea Computer Graphics Society
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• v.6 no.4
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• pp.1-7
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• 2000

Traditionally, three dimension model s have been used for building virtual worlds, and a data structure called the "scene graph" is often employed to organize these 3D objects in the virtual space. On the other hand, image-based rendering has recently been suggested as a probable alternative VR platform for its photo-realism, however, due to limited interactivity. it has only been used for simple navigation systems. To combine the merits of these two approaches to object/scene representations, this paper proposes for a scene graph structure in which both 3D models and various image-based scenes/objects can be defined. traversed, and rendered together. In fact, as suggested by Shade et al. [1]. these different representations can be used as different LOD's for a given object. For in stance, an object might be rendered using a 3D model at close range, a billboard at an intermediate range. and as part of an environment map at far range. The ultimate objective of this mixed platform is to breath more interactivity into the image based rendered VE's by employing 3D models as well. There are several technical challenges in devising such a platform : designing scene graph nodes for various types of image based techniques, establishing criteria for LOD/representation selection. handling their transition s. implementing appropriate interaction schemes. and correctly rendering the overall scene. Currently, we have extended the scene graph structure of the Sense8's WorldToolKit. to accommodate new node types for environment maps. billboards, moving textures and sprites, "Tour-into-the-Picture" structure, and view interpolated objects. As for choosing the right LOD level, the usual viewing distance and image space criteria are used, however, the switching between the image and 3D model occurs at a distance from the user where the user starts to perceive the object's internal depth. Also. during interaction, regardless of the viewing distance. a 3D representation would be used, if it exists. Finally. we carried out experiments to verify the theoretical derivation of the switching rule and obtained positive results.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.1
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• pp.191-197
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• 2013

Conventional CT and MRI scans produce cross-section slices of body that are viewed sequentially by radiologists who must imagine or extrapolate from these views what the 3 dimensional anatomy should be. By using sophisticated algorithm and high performance computing, these cross-sections may be rendered as direct 3D representations of human anatomy. The 2D medical image analysis forced to use time-consuming, subjective, error-prone manual techniques, such as slice tracing and region painting, for extracting regions of interest. To overcome the drawbacks of 2D medical image analysis, combining with medical image processing, 3D visualization is essential for extracting anatomical structures and making measurements. We used the gray-level thresholding, region growing, contour following, deformable model to segment human organ and used the feature vectors from texture analysis to detect harmful cancer. We used the perspective projection and marching cube algorithm to render the surface from volumetric MR and CT image data. The 3D visualization of human anatomy and segmented human organ provides valuable benefits for radiation treatment planning, surgical planning, surgery simulation, image guided surgery and interventional imaging applications.

• Journal of Korean Neurosurgical Society
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• v.30 no.11
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• pp.1300-1307
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• 2001

Purposes : This study reports the possible causes of seizure recurrence in patients underwent previous epilepsy surgery, and surgical strategy for resection of the additional epileptogenic zone locating at the distant area to the site of first resection. Methods : A total of 10 patients with previous surgery due to intractable epilepsy were studied. Five of these underwent standard temporal lobectomy, four extratemporal resection, and one corticoamygdalectomy. Seizure outcome of these were class III-IV. Evaluation methods for reoperation included MRI, 3D-surface rendering of MRI, PET, prologned video-EEG recording with surface electrodes and subdural grid electrodes. Additional resection was done in the frontal lobe in two, in the temporal lobe in three, in the parietal lobe in two, and in the supplementary sensori-motor area in two. Tumor in the superior frontal gyrus in the left hemisphere was removed in one patient. Extent of resection was decided based on the results of ictal subdural grid EEGs and MRI findings. Awake anesthesia and electrocortical stimulation were performed in the two patients for defining the eloquent area. Results : Histopathologic findings revealed extratemporal cortical dysplasia in six, hippocampal sclerosis and cortical dysplasia of the temporal neocortex in one, neuronal gliosis in two, and meningioma in one. Previous pathology of the five patients with cortical dysplasia in the second operation was hippocampal sclerosis plus cortical dysplasia of the temporal neocortex. After reoperation, seizure outcomes were class I in six, class II in three, class III in one at the mean follow-up period of 17.5 months. Characteristically, patients in class II-III after reoperation showed histopathologic findings of hippocampal sclerosis plus temporal neocortical cortical dysplasia plus extratemporal cortical dysplasia. Conclusions : Seizure recurrence after epilepsy surgery was related with the presence of an additional epileptogenic zone distant to the site of first operation, and the majority of the histopathology of the surgical specimens was cortical dysplasia. In particular, hippocampal sclerosis plus temporal neocortical cortical dysplasia was highly related with seizure recurrence in patients with previous operation. In these patients, multimodal evaluation methods were necessary in defining the additional epileptogenic zone.

• Spatial Information Research
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• v.23 no.6
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• pp.57-66
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• 2015

Recently, the utilization of geospatial open platforms has been constantly increased and the interest in 3D geospatial data such as terrain, building and shopping mall has been increased significantly. In particular, rather than simplified 3D geospatial data, interest in high-precision 3D geospatial data which similarly represents the real world objects has increased significantly. In order to satisfy the demand for such the high-precision 3D geospatial data, various kinds of 3D geospatial open platforms has been developed and has provided services on the web. However, most of the 3D geospatial open platforms have been used plug-in module in order to ensure a fast 3D rendering performance on the web, despite the many problems such as difficulty of the installation, no supporting of cross browser/operating system and security issues. In addition, recently, the existing 3D geospatial open platforms based on plug-in module are facing a serious problem, by declaring the NPAPI service interruption in Chrome and Firefox browsers. In this study, we presents the design and implementation of a new 3D geospatial open platform based on HTML5/WebGL technology without the use of plug-ins. Such the new 3D geospatial open platform based on HTML5/WebGL may support cross browsers such as IE, Chrome, Firefox, Safari and cross OS platforms such as Windows, Linux, Mac and mobile OS platforms.