• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5D
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• pp.671-677
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• 2011

A diversity of railway network function enhancement projects such as the double tracking, electrification, and direct operation have been actively executed to improve the railway service. When the new rapid transit is provided, how many people will use it instead of other transports? How will the railway choice behavior be changed? Accordingly, in this paper, the applicability of diverted travel demand forecast methods, by Revealed Preference(RP) and Stated Preference(SP) data was reviewed for Daegu metropolitan rail rapid transit service. As the result of combining RP and SP data, including the sequential and simultaneous approach, the total travel time and travel cost parameters are of the right sign and are highly significant. The simultaneous approach is more efficient in terms of the estimation of coefficients. In particular, methods to improve validity of the Mixed RP/SP models, when RP data is used proportionally, the diverted travel demand can be easily identified by railway fare and travel time service level. Therefore, it is considered that this will practically apply even in other regions as well as Daegu metropolitan railway.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.3
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• pp.124-131
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• 2007

Research field on crowd animation can be classified into two major categories. One is to offer realism of the crowd motion and the other is to improve speed of the animation. For the last decade, a lot of research on realism and behavior of crowd have been presented. But lately, research on improving speed seems like more interesting. Therefore, in this paper, we conducted an experiment to analyze what is the main bottleneck of crowd animation. As the result, we find out one of the most important bottleneck is the number of joints transformed in each animation frame. In order to resolve this problem we propose a novel level-of-detail technique 'motion level-of-detail', which is a joint-reduction technique operated in the pre-processing time. We used a non-linear optimization, SQP (sequential quadric programming), to generate the low detailed motions.

• Journal of the Korean Vacuum Society
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• v.17 no.2
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• pp.81-89
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• 2008

Atomic behavior during ion beam sputtering was investigated by using classical molecular dynamics simulation. When Ar ion bombards on Au and Pd(001) surface with various incidence energies and angles, some atoms which gained substantial energy by impacting Ar ion were sputtered out and, simultaneously, others were landed on the surface as if surface atoms were redeposited. It was observed that the redeposited atoms are five times for Au and three times for Pd as many as sputtered atoms irrespective of both incidence energy and angle. From sequential ion bombarding calculations, contrary to the conventional concepts which have described the mechanism of surface pattern formation based only on the erosion theory, the redeposition atoms were turned out to play a significant role in forming the surface patterns.

• Fire Science and Engineering
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• v.30 no.1
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• pp.31-36
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• 2016

This study investigates the characteristics of thermal decomposition of an epoxy-based intumescent paint using thermogravimetric analysis (TGA) and numerical simulation. A mathematical and numerical model is introduced to describe mass loss profiles of the epoxy-based intumescent coating induced by the thermal decomposition process. The decomposition scheme covers a range of complexity by employing simplified 4-step sequential reactions to describe the simultaneous thermal decomposition processes. The reaction rates are expressed by the Arrhenius law, and reaction parameters are optimized to fit the degradation behavior seen during thermogravimetric (TG) experiments. The experimental results show a major 2-step degradation under nitrogen and a 3-step degradation in an air environment. The experiment also shows that oxygen takes part in the stabilization of the intumescent coating between 200 and $500^{\circ}C$. The simulation results show that the proposed model effectively predicts the experimental mass loss as a function of time except for temperatures above $800^{\circ}C$, which were intentionally not included in the model. The maximum error in the simulation was less than 3%.

• Archives of Reconstructive Microsurgery
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• v.8 no.2
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• pp.97-107
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• 1999

The osteogenic capacity of the vascularized periosteum autograft has been extensively demonstrated by experimental works. The objective of this study was to characterize the behavior of experimental model of vascularized periosteal flap(VPF) by observing sequential stages of osteogenesis after simulated VPF in rabbits. In experimental group, segmental resection of bone including the periosteum was performed in 22 radii of 22 New Zealand white rabbits preserving the periosteal circulation of median artery to the periosteum. In order to simulate the transplantation of VPF, the vascular pedicle consisting of median artery and veins was dissected from adjacent soft tissue and the periosteum was longitudinally incised to remove the bone followed by repair of the periosteum. From the first to sixteenth week after the simulated VPF, the changes in VPFs were observed by radiological, light microscopical, scanning electron microscopical methods and the activity of osteocalcin was measured by immunohistochemical method. In control group, the bone tissue and periosteum were completely removed from the mid-shaft of radius and the findings were observed by radiological and light microscopical methods. From the results of this study, it is demonstrated that the experimental model of VPF is vigorously and uniformly osteogenic. Therefore it is thought that VPF can be used as a measure to treat bone defect of shaft of long bone.

• Journal of Digital Contents Society
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• v.14 no.2
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• pp.215-222
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• 2013

NAND flash memory-based Solid State Drives (SSD) have lots of merits compared to traditional hard disk drives (HDD). However, random write in SSD is still far slower than sequential read/write and random read. There are two independent approaches to resolve this problem: 1) using part of the flash memory blocks as log blocks, and 2) using internal write buffer (DRAM or Non-Volatile RAM) in SSD. While log blocks are managed by the Flash Translation Layer (FTL), write buffer management has been treated separately from FTL. Write buffer management schemes did not use the exact status of log blocks and log block management schemes in FTL did not consider the behavior of write buffer management scheme. In this paper, we first show that log blocks and write buffer have a tight relationship to each other, which necessitates integrated management of both of them. Since log blocks also can be viewed as another type of write buffer, we can manage both of them as an integrated write buffer. Then we provide three design criteria for the integrated write buffer management scheme which can be very useful to SSD firmware designers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6A
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• pp.550-557
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• 2007

We predict a context of various structures by using Bayesian Networks Algorithms, Three-Dimensional Structures Algorithms and Genetic Algorithms. However, these algorithms have unavoidable problems when providing a context-aware service in reality due to a lack of practicality and the delay of process time in real-time environment. As far as context-aware system for specific purpose is concerned, it is very hard to be sure about the accuracy and reliability of prediction. This paper focuses on reasoning and prediction technology which provides a stochastic mechanism for context information by incorporating various context information data. The objective of this paper is to provide optimum services to users by suggesting an intellectual reasoning and prediction based on hierarchical context information. Thus, we propose a design of user location prediction algorithm using sequential matching with n-size flexible window scheme by taking user's habit or behavior into consideration. This algorithm improves average 5.10% than traditional algorithms in the accuracy and reliability of prediction using the Flexible Window Scheme.

• Journal of Navigation and Port Research
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• v.39 no.4
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• pp.307-312
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• 2015

ARPA(Automatic Radar Plotting Aid) is a device to calculate CPA(closest point of approach)/TCPA(time of CPA), true course and speed of targets by vector operation of relative courses and speeds. The purpose of this study is to develop target acquisition and tracking technology for ARPA Radar implementation. After examining the previous studies, applicable algorithms and technologies were developed to be combined and basic ARPA functions were developed as a result. As for main research contents, the sequential image processing technology such as combination of grayscale conversion, gaussian smoothing, binary image conversion and labeling was deviced to achieve a proper target acquisition, and the NNS(Nearest Neighbor Search) algorithm was appllied to identify which target came from the previous image and finally Kalman Filter was used to calculate true course and speed of targets as an analysis of target behavior. Also all technologies stated above were implemented as a SW program and installed onboard, and verified the basic ARPA functions to be operable in practical use through onboard test.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2834-2851
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• 1997

In this paper, a design and implementation of VHDL compiler front-end, aims at supporting the full-set of VHDL '87 & '93 LRM and carring out the preprocessing of VHDL-to-C, is described. The VHDL compiler front-end includes 1)the symbol tree of analyzed data to represent the hierarchy, the scope and visibility, the overloading and homograph, the concurrent multiple stacks in VHDL, 2)the data structure and supportig routies to deal with the objects, the type and subtype, the attribute and operation in VHDL, 3)the analysis of the concurrent/sequential statements, the behavior/structural descriptions, of semantic token and the propagation of symbol & type to improve the registration and retrieval procedure of analyzed data. In the experiments with Validation Suite, the VHDL compiler front-end could support the full-set specification of VHDL LRM '87 & '93; and in the experiments to asses the performance of symantic token for the VHDL hierachy/visibility/concurrency/semantic checking, the improvement of about 20-30% could be achieved.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.10
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• pp.411-420
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• 2019

Camera model identification has been a subject of steady study in the field of digital forensics. Among the increasingly sophisticated crimes, crimes such as illegal filming are taking up a high number of crimes because they are hard to detect as cameras become smaller. Therefore, technology that can specify which camera a particular image was taken on could be used as evidence to prove a criminal's suspicion when a criminal denies his or her criminal behavior. This paper proposes a deep learning model to identify the camera model used to acquire the image. The proposed model consists of four convolution layers and two fully connection layers, and a high pass filter is used as a filter for data pre-processing. To verify the performance of the proposed model, Dresden Image Database was used and the dataset was generated by applying the sequential partition method. To show the performance of the proposed model, it is compared with existing studies using 3 layers model or model with GLCM. The proposed model achieves 98% accuracy which is similar to that of the latest technology.