• Journal of the Society of Naval Architects of Korea
• /
• v.50 no.3
• /
• pp.190-198
• /
• 2013

In order to predict acoustic pressure distributions by exterior incident wave at Cylindrical Hydrophone Array (CHA) sensor's positions, acoustic pressure analysis is performed by using beam tracing method. Beam tracing method is well-known of reliable pressure analysis methods at high-frequency range. When an acoustic noise source is located at the center of rectangular room, acoustic pressure analysis is performed by using both beam tracing method and Power Flow Boundary Element Method (PFBEM). By comparing with results of beam tracing method and those of PFBEM, the accuracy of beam tracing method is verified. We develop the CHA pressure analysis program by verified beam tracing method. The developed software is composed of model input, sensor array creator, analysis option, solver and post-processor. We can choose a model option of 2D or 3D. The sensor array generator is connected to a sonar which is composed of center position, bottom, top and angle between sensors. We also can choose an analysis option such as analysis frequency, beam number, reflect number, etc. The solver module calculates the ray paths, acoustic pressure and result of generating beams. We apply the program to 2D and 3D CHA models, and their results are reliable.

• Journal of Communications and Networks
• /
• v.15 no.6
• /
• pp.547-558
• /
• 2013

Ultra broadband communication systems operated at THz frequencies will require the thorough knowledge of the propagation channel. Therefore, an extensive measurement campaign of 50 GHz wide indoor radio channels is presented for the frequencies between 275 and 325 GHz. Individual ray paths are resolved spatially according to angle of arrival and departure. A MIMO channel is recorded in a $2{\times}2$ configuration. An advanced frequency domain ray tracing approach is used to deterministically simulate the THz indoor propagation channel. The ray tracing results are validated with the measurement data. Moreover, the measurements are utilized for the calibration of the ray tracing algorithm. Resulting ray tracing accuracies are discussed.

• The Journal of the Acoustical Society of Korea
• /
• v.27 no.1
• /
• pp.1-11
• /
• 2008

To overcome the mid frequency limitation of geometrical acoustic techniques, the phased geometrical method was suggested by introducing the phase information into the sound propagation from the source. By virtue of phase information, the phased tracing method has a definite benefit in taking the interference phenomenon at mid frequencies into account. Still, this analysis technique has suffered from difficulties in dealing with low frequency phenomena, so called, wave nature of sound. At low frequencies, diffraction at corners, edges, and obstacles can cause errors in simulating the transfer function and the impulse response. Due to the use of real valued absorption coefficient, simulated results have shown a discrepancy with measured data. Thus, incorrect phase of the reflection characteristic of a wall should be corrected. In this work, the uniform theory of diffraction was integrated into the phased beam tracing method (PBTM) and the result was compared to the ordinary PBTM. By changing the phase of the reflection coefficient, effects of phase information were investigated. Incorporating such error compensation methods, the acoustic prediction by PBTM can be further extended to low frequency range with improved accuracy in the room acoustic field.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1997.04a
• /
• pp.669-674
• /
• 1997

A sound field in a reverberation room is analyzed by using numerical methods and the SPL distributions are compared to the measurements. In numerical predictions, the BEM is employed in the low frequency range, while sound ray tracing method is used for the high frequency range. In the BEM analysis, the surfaces of the empty reverberation room are assumed as rigid boundaries and the damping coefficients are estimated from the measured absorption coefficient. The comparisons with measurements for 100Hz shows good agreement. In the sound ray tracing analysis, the predicted energy decay are in excellent agreements with theoretical results. It is shown that the energy absorption by air damping plays an important role as frequency becomes higher.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.3B
• /
• pp.297-304
• /
• 2011

MIMO wireless communication embedded systems, and for propagation prediction for indoor and outdoor propagation prediction program incorporates an indoor/outdoor propagation through the simulator can be predicted. This analysis technique developed by the interference between multiple transmitters and a maximum transmission distance issues, the frequency utilization efficiency for a variety of issues, including analysis and prediction becomes possible. Development of the prediction of the conventional methods, but I can consider the environmental characteristics of the ray tracing simulation software to develop and implement an efficient ray tracing, ray tracing techniques and are designed to enable tracked beam analysis of propagation characteristics using information technology by combining the theoretical characteristics of an efficient and well-reflected propagation prediction technique was employed. The frequency of domestic embedded systems, ensure the frequency characteristics and frequency of 3-5GHz band for propagation to investigate the development of local wireless communication technology-based skills needed for securing and jeonpaganseopdeung frequency management techniques to ensure the verification and verified through experiments.

• Korean Journal of Oriental Medicine
• /
• v.12 no.3 s.18
• /
• pp.31-47
• /
• 2006

Nowadays Korean governments use Information Technology to improve the quality of life for a people. One of these tries is building the Food Tracing System based on Information Technology. Koreans have big concern about food that is good for health. The Food Tracing System means that the system can follows, traces, and records every steps of production and delivery of food and its ingredient. And this process should be identified and grouped by using tags, marks, and other methods. For example, producer of ingredient, processing steps of food, delivered place could be traced. In addition to food, medical herbs need consumer's trust in production and delivery. To trace and prosecute contaminated medical herbs, medical herbs also need this kind of Tracing System based on Information Technology. This study shows current medical herbs tracing ways and RFID(Radio Frequency IDentification) technology trend. As preceding study for future RFID based medical herbs tracing system, this study suggests the building plan and scenario of the Medical Herbs Tracing System. The determination of the main body for sticking RFID Tags is very important to design for RFID Traceability System. In this study, the starting point of information to medical herbs is an inspection agency. The Medical Herbs to product domestically or import moved to an inspection agency. An inspection agency bond the RFID Tags to packing of the Medical Herbs after examining the a basic its component. At the same time inspector give the information of production or importation to the Tags. This Tags are moved for logistical process to end point, the Korean medicine agency. The customer confirmed the traceability and certification information of the Medical Herbs. For success tracing of medical herbs, institutional support and close cooperation between related organizations is necessary besides good system design.

• Journal of KIISE:Computing Practices and Letters
• /
• v.15 no.12
• /
• pp.973-977
• /
• 2009

The tracing system means that the system can follows, traces, and records every steps of production and delivery of goods and its ingredient. Specially, Koreans have big concern about food tracing system which is influential for health directly. We were more interested in medical herb using in oriental medicine than any other things. We proposed the process and design of tracing system for medical herb based on RFID(Radio Frequency IDentification) technology in this research. This study shows current medical herb tracing ways and RFID code system by using for world standard. Firstly, We designed the new process of traceability of medical herb with various preceding references based on RFID technology. Secondly we suggest that RFID code configuration using the international standard code(ISO code) and korean agricultural and marine products code for the proposed process. RFID code system is very important because this plays a means of identification for tracing about medical herb. The proposed code system have the elements as Issuing Agency Code, Issuer Number, inspection information, inheritance flag, area code, modified agricultural and marine products code, serial number in 96 Bit length. Lastly We defined the code-generation process in the tracing system.

• Journal of electromagnetic engineering and science
• /
• v.15 no.1
• /
• pp.1-5
• /
• 2015

A high-frequency analysis technique, called the hidden rays of diffraction (HRD), is reviewed in this paper. The physical optics and the rigorous diffraction coefficients of a perfectly conducting wedge illuminated by a plane wave are compared. The physical existence of hidden rays on the shadow boundary is explained in view of the geometric theory of diffraction (GTD). In particular, a systematic tracing of hidden rays and its visualization are precisely described by introducing the concept of the supplementary boundary. The physical meaning of the null-field condition in the complementary region is also explained.

• Journal of Global Scholars of Marketing Science
• /
• v.16 no.4
• /
• pp.1-11
• /
• 2006

Product quality of perishable food is significantly affected by the environment. Technological approaches for tracking and tracing such products have attracted increasing attentions in both research and practice. This paper studies how supermarket can maximize profits of selling perishable food through price adjustment based on real-ime product quality and values. This can be achieved by tracing the value of the perishable food based on an automatic product identification technology Radio Frequency Identification(RFID). With the support of the RFID, an optimization model can be developed to enable product tracking and tracing. The analysis of the model shows promising benefits of applying a dynamic pricing policy and obtains the optimal ordering decision in the respect of deterministic demand function.

• Journal of electromagnetic engineering and science
• /
• v.18 no.4
• /
• pp.242-247
• /
• 2018

This paper studies a convenient electromagnetic field (EMF) compliance assessment for base station installations at a millimeter wave (mmW) frequency. We utilize ray-tracing analysis as a numerical method for examining the wave propagation characteristic. Various installation cases are considered and the important parameters with a significant effect on the maximum power density levels are produced. We finally suggest the several scenarios for the convenient assessment of mmW base stations, which allow us to conduct cost effective computational tests compared with the current assessment procedure in the guideline.