Chang-Hun Kim

• Professor (Full) at Korea University

Internet memes have become an essential tool for online communication and interaction on social media platforms. They reflect a wide range of emotional and cultural elements, thereby serving as effective vectors for rapid information exchange. In this digital age, the popularity and influence of memes highlight the need for innovative communication...

This paper proposes a new data-driven neural network-based fire-flake simulation model. Our model trains a neural network using precomputed fire simulation data. The trained neural network model generates fire flakes in appropriate locations and infers their velocity to make them appear natural to their surroundings. The neural network model consis...

Internet memes have become widely used by people for online communication and interaction, particularly through social media. Interest in meme-generation research has been increasing rapidly. In this study, we address the problem of meme generation as an image captioning task, which uses an encoder–decoder architecture to generate Chinese meme text...

We propose a real time simulation for window frost formation on mobile devices that uses both particles and grids. Previous ice formation methods made heavy demands on both memory and computational capacity because they were designed for a desktop environment. In this paper, a frost skeleton grows around a location touched by the user using particl...

This study proposes the interaction of third-person virtual reality (TPVR) to provide users with a new presence and experience during immersive virtual reality (VR). The proposed TPVR interaction consists of the ability to directly control the virtual environment and objects by utilizing the hands. For this purpose, this study defines the interacti...

We propose a framework for generating, animating, and controlling fire-flakes to correspond with the movements of flame. Not only do fire-flakes themselves display a distinctively complex and elaborate movement, but also they are heavily influenced by where the heat transforms into flame and how the flame moves. It is difficult for designers to gen...

Bitcoin is an online currency that is used worldwide to make online payments. It has consequently become an investment vehicle in itself and is traded in a way similar to other open currencies. The ability to predict the price fluctuation of Bitcoin would therefore facilitate future investment and payment decisions. In order to predict the price fl...

We propose a physics-inspired simulation framework that expresses visual effects of flowing water frozen in glaze or directional icicles. The proposed ice model considers the direction of the water flow, which affects the growth of icicles. Water dynamics are computed using a conventional particle-based simulation. Ice glaze and directional icicles...

In this study, we propose a new method for simulating water responding to human motion. Motion data obtained from motion-capture devices are represented as a jointed skeleton, which interacts with the velocity field in the water simulation. To integrate the motion data into the water simulation space, it is necessary to establish a mapping relation...

This paper proposes a system for predicting increases in virtual world user actions. The virtual world user population is a very important aspect of these worlds; however, methods for predicting fluctuations in these populations have not been well documented. Therefore, we attempt to predict changes in virtual world user populations with deep learn...

We present a new method for adaptively extracting flicker-free surfaces from time-varying nonuniform point-set data such as a hybrid particle–grid water simulation. When particles are irregularly distributed in hybrid simulations, degenerate triangles and holes may occur when constructing surfaces adaptively. These abnormal surfaces appear unexpect...

We propose an efficient framework to realistically simulate foam effects in which 3D water particles from a base water solver are first projected onto 2D screen space in order to reduce computational complexity of finding foam particles. Because foam effects are often created primarily in fast and complicated water flows, we analyze acceleration an...

This paper proposes a method to predict fluctuations in the prices of cryptocurrencies, which are increasingly used for online transactions worldwide. Little research has been conducted on predicting fluctuations in the price and number of transactions of a variety of cryptocurrencies. Moreover, the few methods proposed to predict fluctuation in cu...

The result of implementing opinion analysis from user opinion data (reply) on the Ripple forum (http://www.xrpchat.com/). (CSV)

Python-based crawler source code for community data collection. (ZIP)

The result of implementing opinion analysis from user opinion data (topic) on the Bitcoin forum (https://bitcointalk.org). (CSV)

The result of implementing opinion analysis from user opinion data (topic) on the Ethereum forum (https://forum.ethereum.org/). (CSV)

The result of implementing opinion analysis from user opinion data (reply) on the Ethereum forum (https://forum.ethereum.org/). (CSV)

The result of implementing opinion analysis from user opinion data (topic) on the Ripple forum (http://www.xrpchat.com/). (CSV)

Juggling, which uses both hands to keep several objects in the air at once, is admired by anyone who sees it. However, skillful real-world juggling requires long, hard practice. Therefore, we propose an interesting method to enable anyone to juggle skillfully in the virtual world. In the real world, the human motion has to follow the motion of the...

We propose a simulation framework for expressing cloudy effects and scratches on ice caused by the collision of other objects. Cloudy effects are created and diffused in proportion to the collision on the ice surfaces calculated by a combination of a grid-projection technique and the boundary particle method. To prevent dissipation during the diffu...

We propose a novel method conceptualized from the properties of physics where in particular the shape of a flame is determined by temperature that enables a control mechanism for the intuitive shaping of a flame. We focused on a trade-off issue from computer graphics whereby the turbulent flow that expresses the characteristics of the flame has a t...

We present a new method for the fast simulation of interactions between fluids and solids by incorporating particle-based water flow into an adaptive signed distance field. In some previous methods, the motion of every water particle is checked when simulating the collision with the solid in the coupling process, and the computational cost becomes...

Purpose: The aim of this study was to evaluate the efficacy and the safety of ZD 1839 (Iressa(R)) as a 3rd or 4th line chemotherapy regimen in NSCLC patients who are refractory to a previous chemotherapy regimen. Materials and methods: Twenty-five patients who were refractory to previous chemotherapy were selected for this study. The eligible pa...

Purpose: Refractory small-cell lung cancer (SCLC) has a poor prognosis, and current salvage chemotherapy for refractory SCLC, such as CAV (cyclophosphamide, adriamycin, vincristine) or topotecan, has an unsatisfactory outcome, with a response rate and overall survival of less than 10% and 6 months, respectively. This phase II study evaluated the r...

Purpose: With the increased use of chemotherapy for non small cell lung cancer (NSCLC), a growing group of patients can now be considered for second-line chemotherapy. However, guidelines for the second line treatment remain to be developed. The objective of this study was to evaluate the efficacy and safety of the gemcitabine and vinorelbine comb...

Purpose: We performed a phase II trial to evaluate the efficacy and the safety of gemcitabine monotherapy, a pyrimidine antimetabolite, in patients, who had previously failed anthracycline and taxane-based chemotherapy for the treatment of metastatic breast cancer. Materials and methods: Twenty-one patients with metastatic breast cancer, which w...

Purpose: This study was performed to estimate the response rate and toxicity of a combination chemotherapy, which included infusional 5-Fluorouracil, Leucovorin and Docetaxel in the treatment of patients with an advanced gastric carcinoma. Materials and methods: Twenty two advanced gastric cancer patients, with a bidimensionally measurable or an...

In this paper, we propose a method for automatically detecting the times during which game players exhibit specific behavior, such as when players commonly show excitement, concentration, immersion, and surprise. The proposed method detects such outlying behavior based on the game players’ characteristics. These characteristics are captured non-inv...

Timeline Data Timeline for Bioshock Infinite (Timeline_bioshock_infinite.xlsx) and Timeline for Tomb raider (Timeline_tomb_raider.xlsx).

In computational science and computer graphics, there is a strong requirement to represent and visualize information in the real domain, and many visualization data structures and algorithms have been proposed to achieve this aim. Unfortunately, the dataflow model that is often selected to address this issue in visualization systems is not flexible...

In this paper, we present a method for predicting the value of virtual currencies used in virtual gaming environments that support multiple users, such as massively multiplayer online role-playing games (MMORPGs). Predicting virtual currency values in a virtual gaming environment has rarely been explored; it is difficult to apply real-world methods...

It is very difficult and tedious work to synthesize an animation in which a character skillfully controls several balls. This is because all the virtual balls need to be synchronized with the motion of the character temporally and spatially as following the laws of physics. Moreover, a skillful actor is needed for capturing the motion. We introduce...

This section proposes a numerical method for maintaining a dynamic rolling motion of animated gaseous phenomena, such as smoke, that avoids dissipation due to numerical error. It compensates for the errors induced by a semi-Lagrangian scheme using an error estimate for each time interval. And it develops a new advection term and perform vortex adve...

The burning of a sheet of cellulose-based material, such as paper or cloth, involves uneven shrinkage which causes wrinkling.

This section proposes a direct motion tree (DMT) method to speedup the particle-solid coupling process in fluid simulations through prediction of the particle motion path. The DMT method is adaptively constructed, and each node stores the signed distance to the object, as well as a list of particles that are likely to collide with that.

This chapter shows the essential part to implement real-time visual effects. An application such as a game should run in real time to interact with users. For smooth interaction, its rendering speed should be more than 30 FPS (33 ms per frame). Due to recent technological advances computation power becomes very high, but it is almost impossible to...

This section introduces a new fluid animation technique in which liquid and gas interact with each other, using the example of bubbles rising in water. In contrast to previous studies which only focused on one fluid, this system considers both the liquid and gas simultaneously. In addition to the flowing motion, the interactions between liquid and...

This chapter introduces the fundamental theory for understanding the entire contents of this book. A method to solve fluid equation for fire, water, and smoke simulations is explained. And also, background knowledge and research trends for modeling the natural environment such as ice formation are described. In addition to fluid dynamics, a couplin...

We propose a hybrid signed distance field (SDF) method for reconstructing the detailed surface of a model as it changes from a solid state to a liquid state. Previous particle-based fluid simulations suffer from a noisy surface problem when the particles are distributed irregularly. If a smoothing scheme is applied to reduce the problem, sharp and...

In this study, we investigated the number of categories of veterinary medical devices registered by Animal and Plant Quarantine Agency (QIA) by 2013. We also analyzed the sales of the veterinary medical devices reported from Korea Animal Health Product Association (KAHPA) from 2011 to 2013. The registration rate of veterinary medical devices has sh...

A nationwide survey on radiation safety management in Korean animal hospitals was conducted. By 2013, 53 radiation generators were registered as veterinary medical devices (41 X-ray generators and 12 computed tomography scanners). Additionally there were six approved laboratories for radiation equipment and protection facility, and five approved la...

This paper presents how to track the surface of a multiphase fluid more accurately by using the particle level set method with anisotropic instead of spherical particles. While we use the weighted version of principal component analysis (WPCA) to construct the anisotropic particles, its computational cost is high. We adopt the distribution of parti...

This paper proposes a new procedure for generating a displaced butterfly subdivision surface from multiple images. First, point geometry of the target object is recovered by combining LDC(Layered Depth Cube) surfel sampling scheme with the concept of visual hull based on the input images. Then the subdivision surface is generated approximating to t...

BACKGROUND The prevalence and economic burden of chronic obstructive pulmonary disease (COPD) are increasing worldwide. However, little information is available concerning COPD-associated health care use and costs in Korea. OBJECTIVE To analyse 1) health care use, medical costs and medication use in 2009, and 2) changes in costs and medication use...

The pumps of electro-hydrostatic actuators operate most frequently in boundary lubrication speed range, as they compensate for the position control errors as a control element. When conventional swash plate type piston pumps are applied to electro-hydrostatic actuators, the frictional power losses as well as the wear rate of sliding components, suc...

The progression pattern of brain structural changes in patients with isolated cerebrovascular disease (CVD) remains unclear. To investigate the role of isolated CVD in cognitive impairment patients, patterns of cortical thinning and hippocampal atrophy in pure subcortical vascular mild cognitive impairment (svMCI) and pure subcortical vascular deme...

Background A large number of Alzheimer’s disease (AD) studies have focused on medial temporal and cortical atrophy, while changes in the basal ganglia or thalamus have received less attention. Objective The aim of this study was to investigate the existence of progressive topographical shape changes in the basal ganglia (caudate nucleus, putamen,...

This paper presents a new automated behavior analysis system using a trajectory clustering method for massive multiplayer online games (MMOGs). The description of a player’s behavior is useful information in MMOG development, but the monitoring and evaluation cost of player behavior is expensive. In this paper, we suggest an automated behavior anal...

This paper introduces a combustion model of heat transfer and fuel consumption for the propagation of a fire front on a point cloud surface. The heat transfer includes the heat advection by the airflow as well as diffusion, chemical reaction, and heat loss to generate complex, but controllable heat flows with a designed airflow velocity. For the st...

In this paper, a new system for evaluating interface usability through the analysis of repeated patterns is proposed. The system can be a valuable tool for verifying interfaces and in evaluating their usability by users, both of which are necessary stages in the development and operation of software. This paper concentrates on the repeated patterns...

Subcortical vascular dementia (SVaD), one of common causes of dementia, has concomitant Alzheimer's disease (AD) pathology in over 30%, termed "mixed dementia". Identifying mixed dementia from SVaD is important because potential amyloid-targeted therapies may be effective for treatment in mixed dementia. The purpose of this study was to discriminat...

We propose the primitive tree, a novel and compact space-partition method that samples and reconstructs a distance field with high accuracy, even for regions far from the surfaces. The primitive tree is based on the octree and stores the indices of the nearest primitives in its leaf nodes. Most previous approaches have involved a trade-off between...

This paper presents a particle-grid method to simulate the generation of opaque ice which has air bubbles in it. Water temperature is diffused over a grid, and the exchange of dissolved air between ice and water particles is simulated. We render a particle as an air bubble if it has sufficient air. Otherwise, it is treated as a cloudy volume by dis...

Patients with early-onset Alzheimer's disease (EOAD) are reported to be different from those with late-onset Alzheimer's disease (LOAD) in terms of neuropsychological and neuroimaging findings. In this study, we aimed to compare the longitudinal volume changes of 6 subcortical structures (the amygdala, hippocampus, thalamus, putamen, globus pallidu...

This paper presents a new framework for the semi-automatic synthesis of an inhomogeneous texture from a theoretically infinite number of input exemplars. Our algorithm generates a result with natural multiway transitions, maintaining a reasonable synthesis time to keep interactivity. We introduce intermediate textures between multiple exemplars, ca...

We introduce a biologically motivated simulation technique for the realistic shape deformation of drying leaves. In contrast to skeleton‐based leaf deformation, our approach simulates the whole leaf surface to capture the fine details of desiccated leaves. We represent a leaf as a triangulated double‐layer structure that consists of a Delaunay tria...

In this study the flow rate-to-pressure difference characteristics of short-tube type damping orifices for an aircraft door damper were investigated by CFD analyses and experiments. As the design parameters of the damping orifice its diameter, inlet and outlet angle, tube length and the viscosity of the working fluid were taken into consideration....

Controlling shapes is a challenging problem in a multi-phase fluid simulation. Bubble particles enable the details of air bubbles to be represented within a simulation based on an Euler grid. We control the target shapes of bubbles by the gradient vectors of the signed distance field and attraction forces associated with control particles. Our hybr...

The warm shrink fitting process is generally used to assemble automobile transmission parts (shafts/gears). However, this process causes a deformation in the addendum and dedendum of the gear depending on the fitting interference and gear profile, and this deformation causes additional noise and vibration between the gears. To address these problem...

This paper presents analytic solutions to the integral moving least squares (MLS) equations originally proposed by Shen et al. by choosing another specific weighting function that renders the numerator in the MLS equation unitless. In addition, we analyze the original method to show that their approximation surfaces (i.e. enveloping surfaces with n...

We address the computational resource requirements of 3D example-based synthesis with an adaptive synthesis technique that uses a tree-based synthesis map. A signed-distance field (SDF) is determined for the 3D exemplars, and then new models can be synthesized as SDFs by neighborhood matching. Unlike voxel synthesis approach, our input is posed in...

The burning of a sheet of cellulose-based material, such as paper or cloth, involves uneven shrinkage which causes wrinkling. We simulate this geometrically complicated phenomenon by modeling the effects of heat transfer, shrinkage and partial ablation on a thin shell. A strain-limitation technique is applied to a two-layer structure of springs arr...

For a realistic entertainment experience, home entertainment systems require the ability to handle rich and detailed human facial expressions; this consumes huge amounts of storage. We present a progressive octree-based mesh compression framework optimized for human face models in game applications. We define the octree data structure in spherical...

We present a simple yet robust signed distance field (SDF) generator based on recent GPU architectures. In our approach, the squared Euclidean distance is calculated for each triangle face in parallel, and then an optimized stream reduction process is used to find the shortest distance. During this process, the stream reduction operation acts like...

We present a novel approach to adaptive navigation in the interactive virtual world by using data from the user. Our method constructs automatically a navigation mesh that provides new paths for agents by referencing the user movements. To acquire accurate data samples from all the user data in the interactive world, we use the following techniques...

Abstract By modeling mass transfer phenomena, we simulate solids and liquids dissolving or changing to other substances. We also deal with the very small-scale phenomena that occur when a fluid spreads out at the interface of another fluid. We model the pressure at the interfaces between fluids with Darcy's Law and represent the viscous fingering p...

Understanding pinchoff in a liquid-liquid jet is one of the fundamental problems in the physics of fluid. Pinchoff has a wide variety of applications, such as in ink-jet printers. We have need a phase-field model to numerically investigate the breakup of a forced liquid jet into drops in immiscible liquid-liquid systems. In the phase-field model, t...

Abstract We propose a fast and effective technique to improve sub-grid visual details of the grid based fluid simulation. Our method procedurally synthesizes the flow fields coming from the incompressible Navier-Stokes solver and the vorticity fields generated by vortex particle method for sub-grid turbulence. We are able to efficiently animate smo...

In grid-based uid simulation, subgrid-scale uid is dicult to represent realistically. We have come to describe such small scale details eectively, even on a coarse grid by using escaped particles. These particles, when simulated through smooth particle hydrodynamics, allow the illustration of dynamic and realistic uids. Particles in SPH have a forc...

The eect of surface tension is dynamically and realistically represented within a multiphase uid simulation. Air bubbles are seeded with 'bubble particles,' which move randomly. These molecule-like movements modify the surface of the air bubbles and generate turbulence in the water. The surface tension between air bubble and water, determined by th...

We present a fast 3D shape deformation method that achieves smoothly deformed result by approximating a rigid transformation based on moving least squares (MLS). Our modified MLS formulation reduces the computation cost for computing the optimal transformation of each point and still keeps the rigidity of the deformed results. Even complex geometri...

We present a physics-based blending method for the second order algebraic implicit surface. Unlike other traditional blending techniques, the proposed method avoids complex mathematical operations and unwanted artifacts like bulge, which have highly limited the application of the second order algebraic implicit surface as a modeling primitive in sp...

In MMORPG development process, spreadsheet based data management has advantages in the handling of functions and analysis of large data set. But it has limitations in inserting, deleting, searching and relational management of that. In this paper, we proposed the spreadsheet based tool model for large data set for MMORPG development. Our system can...

This paper presents a multi-phase fluid simulation that realistically represents small scale details. We achieve this by creating escaped particles based on physical methods. Escaped particles are the remained particles after correcting levelset. Generation of escaped particles in this paper differs from previous works; this fluid simulation is ext...

Developing suitable interpolation methods to simulate dynamic motions of continuous materials such as fluids is an important problem. In this paper, we propose a novel method to enforce the divergence condition to the interpo-lated velocity field by moving least squares, by means of the diffusive derivatives and moving divergence constraints that a...

We propose a hybrid method for simulating multiphase fluids such as bubbly water. The appearance of subgrid visual details is improved by incorporating a new bubble model based on smoothed particle hydrodynamics (SPH) into an Eulerian grid-based simulation that handles background flows of large bodies of water and air. To overcome the difficulty in...

For the nonlinear behaviors of the actuator and servo system of the optical disk player, a fuzzy control is introduced. Focus servo controls the laser beam to focus on the playing surface of the disc by vertical movement of the objective lens. The change of the distance between the objective lens and the disc must be within the allowable focus erro...

In closed-die hot forging, a billet is formed in dies such that the flow of metal from the die cavity is restricted. Some parts can be forged in a single set of dies, whilst others, due to shape complexity and material flow limitations, must be shaped in multi sets of dies. The purpose of a performing operation is to distribute the volume of the pa...

Type 2 compressed natural gas(CNG) storage vessels for automobiles are becoming widely used. They are not only supplied to automakers in Korea, such as Hyundai Motors, but increasingly, they are being exported overseas. Autofrettage is a process that produces beneficial residual stresses in a vessel by subjecting it to excessive internal pressure....

Several servo mechanisms, such as focusing, spindling, tracking and sledding, are continuously balanced to make compact disc player (CDP) to play audio or video contents. However, due to the inconsistent uneven surface of the disc, the speed control of a spindle motor along the track radius, and unexpected random shock; the servo mechanism is very...

We propose a novel method of controlling a multi-phase fluid so that it flows into a target shape in a natural way. To preserve the sharp detail of the target shape, we represent it as an implicit function and construct the level-set of that function. Previous approaches add the target-driven control force as an external term, which then becomes at...

We present a new geometry compression algorithm for manifold 3D meshes based on octree coding. For a given mesh, regular volume grids are built with an adaptive octree. For each grid point, a binary sign, which indicates inside or outside of the mesh, is generated based on the distance to the mesh. In each leaf cell having a vertex, a least square...

Fitting process carried out in automobile transmission assembly line is classified into three classes: heat fitting, press fitting, and their combined fitting. Heat fitting is a method that heats gear to a suitable range under the tempering temperature and squeezes it toward the outer diameter of shaft. Its stress depends on the yield strength of g...

We propose an algorithm profiling mesh geometry which consists of triangle soup. Our profile is set of polygons in vector format. We construct a profile by calculating intersection lines from each triangle and profiling plane, and connect the lines. To avoid singularity problem, we classified configurations of triangle and the plane, and process it...

We propose a new method for simplifying polygonal models while retaining salient features. We extract ridge and valley features defined by means of curvature derivatives on the model surface. We combine this extraction with a simplification technique so as to construct coarse models with features preserved. Experimental results have better quality...

We propose a new method of extracting feature lines from a 3D scan model. Given an unstructured 3D triangle mesh containing texture information, we use model feature map (MFM), which is a 2D map that abstracts the variation of texture and curvature in the 3D model. The MFM is created from both a texture map and a curvature map, which are produced s...

Implicit surface fitting is a promising approach to finding ridges and valleys in discrete surfaces, but existing techniques are time-consuming and rely on user-supplied tuning parameters. We use a modified MLS (moving-least-squares) approximation technique to estimate the local differential information near a vertex by means of an approximating su...

Implicit surface fitting is a promising approach to finding ridges and valleys in discrete surfaces, but existing techniques are time-consuming and rely on user-supplied tuning parameters. We use a modified MLS (moving-least-squares) approximation technique to estimate the local differential information near a vertex by means of an approximating su...

The body-brain coevolution of aerial life forms has not been developed as far as aquatic or terrestrial locomotion in the field of artificial life. We are studying physically simulated 3D flying creatures by evolving both wing shapes and their controllers. A creature's wing is modeled as a number of articulated cylinders, connected by triangular fi...

This paper describes a method for controlling the multi-phase smoke animation that uses Lagrangian particles. Previous methods need several den- sity fields to simulate different types of smoke. We use a single field, which is more like a natural phenomenon to obtain the interactive motions of fluid. Also, whereas existing methods which apply contr...

This sketch presents a method to control liquids so that they flow into a target shape in a natural way. To avoid the oscillation and preserve the sharp detail of the target shape, we integrate the target-driven force into the projection step. So we require no post-optimization process for divergence-free condition at the liquid interface. Addition...

This paper improves inhomogeneous Wang tiles to allow user's control. The algorithm takes two source images and a low resolution, two colored guide image as an input, and results non-periodic inhomogeneous image according to user's guide. The method requires at least 128 tiles for both controllability and non-periodicity. This framework also used t...

At interfaces between different fluids, properties such as density, viscosity, and molecular cohesion are discontinuous. To animate small-scale details of incompressible viscous multi-phase fluids realistically, we focus on the discontinuities in the state variables that express these properties. Surface tension of both free and bubble surfaces is...

We propose a numerical method for maintaining a dynamic rolling motion of animated gaseous phenomena, such as smoke, that avoids dissipation due to numerical error. We compensate for the errors induced by a semi-Lagrangian scheme using an error estimate for each time interval. We develop a new advection term and perform vortex advection based on a...