• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.348-353
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• 2008

Despite the increasing popularity of wireless sensor network, indoor positioning using low power IEEE 802.15.4 compliant radio had attracted an interest of many researchers in the last decade. Old fashionable indoor location sensing information has been presented in dull and unpleasant 2D image standard. This paper focused on visualizing high precision 3 dimensional RSSI-based (received signal strength indication) spatial sensing information in an interactive virtual reality on PDA. The developed system operates by capturing and extracting signal strength information at multiple pre-defined reference nodes to provide information in the area of interest, thus updating user's location in 3D indoor virtual map. VRML (Virtual Reality Modeling Language) which specifically developed for 3D objects modeling is utilized to design 3D indoor environment.

• The KIPS Transactions:PartD
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• v.12D no.1 s.97
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• pp.111-120
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• 2005

Software development creates many product that class components, Class Diagram, form, object, and design pattern. So this Paper suggests Index/XML Sequence Relation information system for product abstraction and classification, the system of design product Sequence Relation abstraction which can store, reuse design patterns in the meta modeling database with pattern Relation information. This is Index/XML Sequence Relation system which can easily change various relation information of product for product abstraction and classification. This system designed to extract and classify design pattern efficiently and then functional indexing, sequence base indexing for standard pattern, code indexing to change pattern into code and grouping by Index-ID code, and its role information can apply by structural extraction and design pattern indexing process. and it has managed various products, class item, diagram, forms, components and design pattern.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.201-205
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• 1997

With the recent advance of Web and its associated technologies, information sharing on distribute computing environments has gained a great amount of attention from many researchers in many application areas, such as medicine, engineering, and business. One basic requirement of distributed medical consultation systems is that geographically dispersed, disparate participants are allowed to exchange information readily with each other. Such software also needs to be supported on a broad range of computer platforms to increase the software's accessibility. In this paper, the development of world-wide-web based medical consultation system or radiology imaging is addressed to provide the platform independence and great accessibility. The system supports sharing of 3-dimensional objects. We use VRML (Virtual Reality Modeling Language), which is the de-facto standard in 3-D modeling on the Web. 3-D objects are reconstructed from CT or MRI volume data using a VRML format, which can be viewed and manipulated easily in Web-browsers with a VRML plug-in. A Marching cubes method is used in the transformation of scanned volume data set to polygonal surfaces of VRML. A decimation algorithm is adopted to reduce the number of meshes in the resulting VRML file. 3-D volume data are often very large-sized, and hence loading the data on PC level computers requires a significant reduction of the size of the data, while minimizing the loss of the original shape information. This is also important to decrease network delays. A prototype system has been implemented (http://netopia.snu.ac.kr/-cyber/). and several sessions of experiments are carried out.

• Journal of Energy Engineering
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• v.2 no.1
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• pp.28-37
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• 1993

This paper describes the development of a dynamic model of 1,000 MW$\_$e/ nuclear power plant including its local and integrated control system. The model was constructed using the Modular Modeling System (MMS) developed by the Electric Power Research Institute (EPRI) to provide an efficient, economical and user-friendly computer code for use in the analysis of the dynamic performance of nuclear and fossil power plants in conjunction with the Advanced Continuous Simulation Language (ACSL). Steady state for full load and transient results for turbine power step changes of loft are presented in this paper. The model includes most major components of a 1,000 MW$\_$e/ nuclear power plant and it can readily be modified to simulate a specific power plant. This procedure greatly reduces the analysis and modeling efforts involved in dynamic simulation of power plants and increases confidence in the analysis results.

• Korean Journal of Computational Design and Engineering
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• v.20 no.1
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• pp.75-83
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• 2015

In the virtual prototyping (VP) of digital products, it is important to provide the people involved in product development with the visualization and interaction of the products, and the simulation of their human machine interaction (HMI) behaviors in interactive 3D virtual environments. Especially, for the HMI behavior simulation, it is necessary to represent them properly and to play them back effectively according to user interaction in the virtual environments. In a conventional approach to HMI behavior simulation, user interface (UI) designers use UI design software tools to generate the HMI behavior of a digital product of interest. Due to lack of reusability of the HMI behavior, VP developers need to analyze and integrate it into a VP system for its simulation in a 3D virtual environment. As this approach hinders the effective communication between the UI designers and the VP developers, it is easy to create errors and thereby it takes significant time and effort especially when it is required to represent the HMI behavior to the finest level of detail. In order to overcome the shortcomings of the conventional approach, we propose an approach for representing the HMI behavior of a digital product using XML (eXtensible Markup Language) and for reusing it to perform the HMI behavior simulation in 3D virtual environments. Based on the approach, a VP system has been developed and applied for the design evaluation of various products. A case study about the design evaluation is given to show the usefulness of the proposed approach.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.1
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• pp.46-54
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• 2008

In this paper, a low-cost impedance spectroscopy system(LCISS) suitable for modeling the electrochemical power sources such as fuel cells, batteries and supercapacitors is designed and implemented. Since the developed LCISS is composed of simple sensor circuits, commercial data acquisition board and LabVIEW software, a graphic language with powerful HMI(Human-Machine Interface), it is expected ta be widely used in substitution of the expensive EIS instruments. In the proposed system, the digital lock-in amplifier is adopted to achieve the accurate measurements even in the presence of the high level of noises. The developed hardware and software is applied to measure the impedance spectrum of the Ballard Nexa 1.2kW proton exchange membrane fuel cell stack and an equivalent impedance model is proposed based on the measurement results. The validity of the proposed equivalent circuit and the developed system is proven by the measurement of the ac power losses of the PEM fuel celt stack by the ripple current.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.5_6
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• pp.335-346
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• 2004

PtolemyII is an environment that supports heterogeneous modeling and design of concurrent systems such as embedded system. PtolemyII has several Domains which are physical rules to determine the way of communicating between components. PtolemyII has 11 domains such as PetriNet, Timed Multitasking, SR etc. Components of System can be specified using appropriate domains for their properties. Communicating Sequential Processes(CSP) is implemented as formally designed CSP domain, in PtolemyII. But CCS didn't be implemented as a domain. It is a kind of Process Algebra language which can be used for specifying and verifying concurrent systems formally. Thus, in this paper we implemented CCS domain. And that permitted developers using PtolemyII to use the same modeling pattern used in PtolemyII and to make system specifications in the base of the formal semantics of CCS. This caused the diversity of PtolemyII domains and the power of expression was improved. This paper will explain the structure of CCS domain implemented in PtolemyII and the way of implementing it.

• The Journal of the Acoustical Society of Korea
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• v.38 no.5
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• pp.607-613
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• 2019

This paper proposes LF-MMI (Lattice Free Maximum Mutual Information)-based acoustic modeling using external knowledge for speech recognition. Note that an external knowledge refers to text data other than training data used in acoustic model. LF-MMI, objective function for optimization of training DNN (Deep Neural Network), has high performances in discriminative training. In LF-MMI, a phoneme probability as prior probability is used for predicting posterior probability of the DNN-based acoustic model. We propose using external knowledges for training the prior probability model to improve acoustic model based on DNN. It is measured to relative improvement 14 % as compared with the conventional LF-MMI-based model.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.1
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• pp.64-73
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• 2019

The manufacturing companies under Make-To-Order (MTO) production environment face highly variable requirements of the customers. It makes them difficult to establish preemptive production strategy through inventory management and demand forecasting. Therefore, the ability to establish an optimal production schedule that incorporates the various requirements of the customers is emphasized as the key success factor. In this study, we suggest a process of designing the simulation model for establishing production schedule and apply this model to the case of a flat glass processing company. The flat glass manufacturing industry is under MTO production environment. Academic research of flat glass industry is focused on minimizing the waste in the cutting process. In addition, in the practical view, the flat glass manufacturing companies tend to establish the production schedule based on the intuition of production manager and it results in failure of meeting the due date. Based on these findings, the case study aims to present the process of drawing up a production schedule through simulation modeling. The actual data of Korean flat glass processing company were used to make a monthly production schedule. To do this, five scenarios based on dispatching rules are considered and each scenario is evaluated by three key performance indicators for delivery compliance. We used B2MML (Business To Manufacturing Markup Language) schema for integrating manufacturing systems and simulations are carried out by using SIMIO simulation software. The results provide the basis for determining a suitable production schedule from the production manager's perspective.

• The Mathematical Education
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• v.58 no.3
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• pp.367-381
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• 2019

This investigation engaged elementary and middle school pre-service teachers in a task of modeling and explaining the magnitude of $0.14m^2$ and examined their responses. The study analyzed both successful and unsuccessful responses in order to reflect on the patterns of misconceptions relative to pre-service teachers' prior knowledge. The findings suggest a need to promote opportunities for pre-service teachers to make connections between different domains through meaningful tasks, to reason abstractly and quantitatively, to use proper language, and to refine conceptual understanding. While mathematics teacher educators (MTEs) could use such mathematical tasks to identify the mathematical content needs of pre-service teachers, MTEs generally use instructional time to connect content and pedagogy. More importantly, an early and consistent exposure to a combined experience of mathematics and pedagogy that connects and deepens key concepts in the program's curriculum is critical in defining the important content knowledge for K-8 mathematics teachers.