• Journal of the Korea Society of Computer and Information
• /
• v.16 no.9
• /
• pp.185-192
• /
• 2011

The purpose of this paper is to propose the design and implementation of a korean style internet-based test system on the basis of efficiency and stability for middle server. The current assessment system has some unstable elements with regard to transmission procedure, cost, system load and stability. This paper proposes a series of activities for the performance improvement of korean style internet-based test system which finally produced various excellent results in the administration of expense control, human resources, and special operational affairs. The proposed system's technological factors using middle server have been tested through a basic simulation pilot system. Actual development procedure starts from the analysis required by improving the shortcomings of existing internet-based test systems. A efficiency comparison with existing system and newly developed system was made in the area of number of operators, abnormal processing, system maintenances. Korean style internet-based test system using middle server has shown great efficiency increased to the maximum of 2 times about the effectiveness of processing for various parts. The korean style internet-based test system using middle server have been given good evaluations with regard to the convenience of their use and the management system for operators and supervisors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.4
• /
• pp.477-483
• /
• 2008

The paper introduces mobile handset multi-band chip antenna to be used on meander line PIFA structure and parasite patch. The proposed antenna uses an FR-4 substrate. The top layer is consist of meander lines PIFA structure to implement GSM900 and is connected with each rad and meander line on the via-hole for maximize space efficiency. The middle layer is designed with the signal line and gap to implement a DCS and PCS bands, the bottom layer which is added to a parasite patch on the ground can be show an adjust of frequency and impedance character by the connection of the radiators of middle layer and coupling. The fabricated antenna with the dimension of $28{\times}6{\times}4\;mm^3$. The ground plane a dimension of $45{\times}90\;mm$, designed by a commercial software CST simulator. The experimental results show that the bandwidth for(VSWR<3) is 90($875{\sim}965$) MHz in GSM900 band operation and 380($1,670{\sim}2,050$) MHz in DCS, PCS band operation. The maximum gains of antenna are 0.25 dBi, 3.65 dBi and 3.3 dBi at resonance frequencies and it has omni-directional pattern practically.

• Elastomers and Composites
• /
• v.48 no.2
• /
• pp.172-179
• /
• 2013

Impact modifier reinforced polymers are frequently used. In this study, Izod impact test has been simulated to analyze the mechanism of impact reinforcement of Nylon6 which contains impact modifier. The modeling of rubber particles added to Nylon6 as an impact modifier has been attempted. Based on the modeling, simulation of Izod impact test has been performed to observe the distribution and direction of stress at the cross-section of impact specimen. Three computer simulation models for Nylon6 were investigated. Those were without impact modifier, containing impact modifier without surface treatment, and containing impact modifier with surface treatment in the Nylon6. Simulation results showed that the stress which originated at the notch surface propergated to the inside of specimen round a impact modifier. In addition to that, impact modifier reinforced Nylon6 specimen showed low stress ditribution in the cross-section specially at notch surface. Principal stress in perpendicular direction to crack was also lowered in impact modifier reinforced Nylon6. These enhanced impact resistance reduced and crack propergations. Through this study it was realized that the computer simulation can be utilized to investigate the property enhacement of composite materials.

• Archives of design research
• /
• v.17 no.2
• /
• pp.425-436
• /
• 2004

A new design field called eDesign appears as if eBiz is an online related business in which an industrialized design creates the individual value added facing a digital revolution. The field of eDesign requires a special design process and management methodology regardless of the fact that human sensitivity will be satisfied through a dehumanized computer technique. However, it is the reality of eDesign that has been dependent upon a simple process or project management tool of general design. In this study, we develop an eDesign platform based on an eDesign process and template mainly focused on eBusiness in order to overcome the wrong situation. The template is a kind of document that has a standardization form. We aim to establish a general process through various case projects, store information using a necessary template, and use for the way of visual communication. We propose a standard of eDesign platform that can be widely applied to the field of design, medium and small enterprises focused on IT businesses or design-team through this project performed as an educational-industrial study. It makes it possible to get a detailed process methodology, which can be applied to many small design related companies that don't have their own process yet, and will be a scale for comparing their own process in which the company has a process of opened standard eDesign with it. In addition, it makes possible a systematic control of the own projects within and outside the firm, accumulating information for the firm through the database, and easy communication. Furthermore, it can be applied to check the process of the project as a checklist, and then it will reduce trial and error repeated for every project that has been done.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.12
• /
• pp.1813-1822
• /
• 2012

The purpose of this study was to determine the optimal mixing conditions of two different amounts of purple barley flour ($X_1$), and olive oil ($X_2$) in baking white pan bread. The experiment was designed according to the central composite design of response surface methodology, which showed 10 experimental points including 2 replicates. The more purple barley flour added, the more weight, yellowness (b-value), hardness, gumminess, and chewiness increased; but the more volume, specific loaf volume, lightness (L-value), and springiness decreased. The greater the amount of olive oil added, the more hardness, cohesiveness, gumminess, and chewiness increased; but the more yellowness (b-value) and springiness decreased. The physical and mechanical properties were affected more by the amount of purple barley flour than by the amount of olive oil. Sensory properties except flavor were more affected by the amount of purple barley flour than by the amount of olive oil.

• Journal of Korean Society of Water and Wastewater
• /
• v.23 no.6
• /
• pp.743-752
• /
• 2009

One of the major problems associated with operation of domestic sewer lines involves hydraulic problems such as insufficient conveyance capacity, exceeding maximum velocity, and deficiency of minimum velocity. It has also been pointed out that influent concentration lower than design concentration of pollutants, which is mainly caused by unidentified inflow and infiltration, degrades the operational efficiency of many sewage treatment plants (STPs). A computer-added analysis method supporting a coupled simulation of sewage quality and quantity is essentially required to evaluate the status of existing STPs and to improve their efficiency by a proper sewer rehabilitation work. In this study, dynamic water quality simulations were conducted using MOUSE TRAP to investigate the principal parameters that governs the changes of BOD, ${NH_4}^+$, and ${PO_4}^{3-}$3- concentrations within the sewer networks based on data acquired through on-site and laboratory measurements. The BOD, ${NH_4}^+$ and ${PO_4}^{3-}$3- concentrations estimated by MOUSE TRAP was lower than theoretical pollution loads because of sedimentation and decomposition in the sewer. The results revealed that sedimentation is a most important factor than other biological reactions in decreasing pollutant load in the sewers of C-city. The sensitivity analysis of parameters pertaining to water quality changes indicated that the effect of the BOD decay rate, the initial DO concentration, the half-saturation coefficient of dissolved BOD, and the initial sediment depth is marginal. However, the influence of settling rate and temperature is relatively high because sedimentation and precipitation, rather than biological degradation, are dominant processes that affect water quality in the study sewer systems.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39C no.2
• /
• pp.199-208
• /
• 2014

Code division multiple access (CDMA) is one of the promising medium access control (MAC) schemes for underwater acoustic sensor networks because of its robustness against frequency-selective fading and high frequency-reuse efficiency. As a way of performance evaluation, sea or lake experiment has been employed along with computer simulation.. In this study, we design the underwater CDMA forward-link transceiver and evaluate the feasibility aginst harsh underwater acoustic channel in water-tank first. Then, based on the water-tank experiment results, we improved the transceiver and showed the improvements in a lake experiment. A pseudo random noise code acquisition process is added for phase error correction before decoding the user data by means of a Walsh code in the receiver. Interleaving and convolutional channel coding scheme are also used for performance improvement. Experimental results show that the multiplexed data is recovered by means of demultiplexing at receivers with error-free in case of two users while with less than 15% bit error rate in case of three and four users.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.11 s.353
• /
• pp.141-148
• /
• 2006

This paper deals with the performance improvement by eliminating loop interference signal and inserting adaptive equalizer for phase compensation in OFDMA based Wibro relay station. The Wibro relay station is used for the extension of communication service area and for throughput improvement of base station. The loop interference is important factor of performance determination of relay station when transmitter and receiver is very closely located. In order to design interference canceller, we generated base-band OFDMA signal and then transmitted the signal along with pilot tones alined with two different combinations for training mode. And then, we generated received fading signal due to the loop interference added noise to the received signal. In the receiver, the transmitted signal is recovered by elimination of the interference signal with channel estimate and compensating phase by adaptive equalizer. The performance improvement was verified by computer simulation which show channel estimation, constellation of signal and BER characteristics according to the variation of SNR ratio.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.11c
• /
• pp.623-631
• /
• 2000

Advanced Life Support Systems (ALSS) are being studied to support human life during long-duration space missions. ALSS can be categorized into four subsystems: Crew, Biomass Production, Food Processing and Nutrition, Waste Processing and Resource Recovery. The System Studies and Modeling (SSM) team of New Jersey-NASA Specialized Center of Research and Training (NJ-NSCORT) has facilitated and conducted analyses of ALSS to address systems level issues. The underlying concept of the SSM work is to enable the effective utilization of information to aid in planning, analysis, design, management, and operation of ALSS and their components. Analytical tools and computer models for ALSS analyses have been developed and implemented for value-added information processing. The results of analyses have been delivered through the Internet for effective communication within the advanced life support (ALS) community. Several modeling paradigms have been explored by developing tools for use in systems analysis. They include object-oriented approach for top-level models, procedural approach for process-level models, and application of commercially available modeling tools such as MATLAB$\^$(R)//Simulink$\^$(R)/. Every paradigm has its particular applicability for the purpose of modeling work. An overview is presented of the systems studies and modeling work conducted by the NJ-NSCORT SSM team in its efforts to provide systems analysis capabilities to the ALS community. The experience gained and the analytical tools developed from this work can be extended to solving problems encountered in general agriculture.

• Journal of Cadastre & Land InformatiX
• /
• v.46 no.2
• /
• pp.211-224
• /
• 2016

Based on the 'Government 3.0', the government opens the public data and encourages the active use in the private sector. Recently, the spatial and statistical information that is one of the public data is being widely used in the various web business as a high value-added information. In this study, we propose an architecture of high-availability, high-reliability and high-performance open platform which can provide a variety of services such as searching, analysis, data mining, and thematic mapping. In particular, we present two different system architectures for the government and the public services, by reflecting the importance of the information security and the respective utilization in the private and public sectors. We also compared a variety of server architecture configurations such as a clustered server configuration, a cloud-based virtual server configuration, and a CDN server configuration, in order to design a cost- and performance-effective spatial-statistical information open platform.