• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.607-610
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• 2009

The abnormal combustion in the running engine results to knocking which increases the pressure and temperature in the cylinder, thereby decreasing the generated power by reducing the thermal efficiency. When the temperature and pressure in the cylinder increased rapidly by knocking, abnormal combustion takes place and the engine power is decreased. To investigate the knocking phenomenon, accelerometers are installed in the cylinder head to monitor and diagnose the vibration signal. As method of signal analysis, the time-frequency analysis method was adapted for acquisition of vibration signal and analyzes engine combustion in the short time. In this experiment, after analyzing time data which is stored in the signal recorder in one unit work (4 strokes: 2 revolutions), the signal with frequency and Wavelet methods with extracted one engine combustion data was also analyzed. Then, normal condition with no knocking signal is analyzed at this time. Hereafter, the experiments made a standard for distinguishing normal and abnormal condition to be carried out in acquisition of vibration signal at all cylinders and extracting knocking signal. In addition, analyzing methods can be diverse with Symmetry Dot Patterns (SDP), Time Synchronous Average (TSA), Wigner-Ville Distribution (WVD), Wigner-Ville Spectrum (WVS) and Mean Instantaneous Power (MIP) in the cold test [2]. With signal processing of vibration from engine knocking sensor, the authors adapted a part of engine /rotor vibration analysis and monitoring system for marine vessels to prevent several problems due to engine knocking

• The Journal of Korean Society for Radiation Therapy
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• v.20 no.2
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• pp.123-130
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• 2008

Purpose: To provide practical education, most universities should be equipped with medical appliances in need. As compensatory measures, Gimcheon College has produced in-house dummy linac and dummy accessories, we are going to report efficiency and its usage. Materials and Methods: Dummy linear accelerator (DLINAC-001) has the same mechanical functions as rotation of gantry and collimation in linear accelerator. In addition, to maximize practical education, we have produced and utilized in-house custom blocks, wedge filters, electron cones and head rests. Results: The in-house produced linear accelerator with the same mechanical functions as the linear accelerator, DLINAC-001 can be effectively used in practicing diverse medical instruments. Conclusion: We have produced dummy linear accelerators and dummy accessories and utilized them in practice classes, which can provide the students with clinical training in diverse fields. Consequently, the students exposed to the maximized educational effectiveness can be easily equipped with the practical competence required in real clinical fields.

• Journal of Platform Technology
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• v.6 no.2
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• pp.3-9
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• 2018

Recently VR environment is used in many areas including mobile learning, smart factory. However HMD(head-mounted display) is required to a dedicated and expensive system with high-end specification. When designing a VR system, it is needed to handle performance, mobility and usability. Many VR applications need to handle diverse sensors and user inputs continuously in a streaming manner. In this paper we design a VR mobile platform and implement a low-cost mobile VR HMD running on the platform. The VR HMD supports 3D contents delivery in a mobile manner. It is used to detect the motion detection based on angle value of a VR player from accelerator and gyro sensor. The MPU-6050, 6-axis sensor, is used to get a sensory value and the sensory value is taken as an input to a VR rendering server on a Unity game engine that is generated 3D images.

• Journal of the Korean Magnetic Resonance Society
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• v.20 no.1
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• pp.27-35
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• 2016

NMR spectrometer has been regarded as essential tool for structure elucidation in variable scientific field as like organic synthesis, natural product and macro protein research. Also NMR can be applied for defining dynamic behavior like ligand and receptor binding. One of advantage of research with NMR is that to be great confident to confirm structure and the measured sample could be recovered. Nevertheless NMR also has a weak points than other spectroscopic methods that require a lot of time for interpreting acquired spectrum and running time due to low sensitivity. For last two decade Bruker has developed hardware and software solution for overcome those weak points. In order to overcome low sensitivity Bruker introduced Cryo and Micro diameter probe head technology. And researcher can reduce the time for routine spectrum processing and interpretation works due to lots of introductions in software solutions for quantification, identification and statistics analysis. With four examples, this article describing those new hardware and software solutions in field of recent pharmaceutical research as follows. - New Horizons for NMR in the Biopharmaceutical Industry - The development and application of solid-state NMR spectroscopy (SSNMR) in pharmaceutical analysis - Assisted NMR Data Interpretation in Synthetic Chemistry - Complete Analysis of New Psychoactive Substances Using NMR.

• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.139-142
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• 1999

Two specimens of Opistognathus iyonis of Family Opistognathidae were collected for the first time at Chwasari Islands, Yokchi-myon, Tongyong-shi, Kyongsangnam-do, Korea. Specimens were catched by fishing on June and Oct. 1998. Opistognathus iyonis was characterized by having large mouth, big eye located anterior part of the head, large black spot on the dorsal fin and lateral line running close below base of dorsal fin. A new Korean name "Huk-Jom-Hu-Ak-Chi" is proposed for this species.

• Journal of Forest and Environmental Science
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• v.30 no.1
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• pp.15-29
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• 2014

This article discusses the state of a community forestry program in a protection forest in Indonesia, which has been running for almost two decades. We found that the program did not achieve its objective mainly because of frequent changes in regulations. There are also activities such as: measuring and mapping working area boundaries, drawing up a work plan, planting, maintenance and security, paying royalties to those who harvest forest resources, and submitting annual reports on land use to the district government head, which have not worked as expected. We also found that the major incentives for local people to participate in the program are getting certificates of management and the program's effectiveness in minimizing land-use conflicts. Participants perceived that their major role on the program is to follow farmer-group directives or government rules. To achieve the program's purposes, farmer groups need technical assistance related to protection-forest management and opportunities for financing.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.4
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• pp.496-507
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• 2010

It is well known that when a high-speed planing craft travels in following seas it experiences long-periodic motions due to low encounter frequency, and it often loses its course keeping stability. Therefore, it is necessary to study the sea-keeping performance and stability of it in the following seas. In this paper, the vertical motions of a planing craft were measured in following regular waves, and the test results were compared with the theoretical results. In the case of the same encounter frequency, non-dimensionalized motion amplitudes become larger as Froude number is higher, and non-dimensionalized motion amplitudes in head waves are larger than those in following waves. The mean values of the motions in following waves are similar to the running attitudes of a craft in calm water at the same Froude number.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.27-36
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• 1999

To have high flatness quality of hot rolled strip in the hot strip finishing mill train, a new inter-stand tension profile measuring device of segmented looper roll type(coined as Flatness Sensing Inter-stand Looper, FlatSIL) and a new flatness control system have been developed in this study. The device measures the strip tension profile across the strip width and informs the strip wave pattern to new flatness control system where work roll bending mode to relieve the strip wave is determined. The existing automatic shape control system which uses laser type shape-meter installed at the outlet of the last finishing mill stand strip tension between down coiler and last finishig mill since the latent wave concealed by the strip tension between down coiler and last finishing mill stand cannot be measured by the laser distance-meter. Thus the existing shape control system is not able to control the flatness through the full strip length. The new flatness control system, however, works for full strip length during strip rolling as far as the tension profile measuring device and work roll bender are on. With the new flatness control system, work roll bender is automatically controller to minimize the latent wave of the running strip and the flatness quality as well as strip travelling stability has been noticeably improved from strip head through body to tail.

• Management Science and Financial Engineering
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• v.14 no.1
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• pp.23-34
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• 2008

In this study, we consider stationary waiting times in a Poisson driven single-server m-node queues in series. We assume that service times at nodes are independent, and are either deterministic or non-overlapped. Each node excluding the first node has a finite waiting line and every node is operated under a FIFO service discipline and a communication blocking policy (blocking before service). By applying (max, +)-algebra to a corresponding stochastic event graph, a special case of timed Petri nets, we derive the explicit expressions for stationary waiting times at all areas, which are functions of finite buffer capacities. These expressions allow us to compute the performance measures of interest such as mean, higher moments, or tail probability of waiting time. Moreover, as applications of these results, we introduce optimization problems which determine either the biggest arrival rate or the smallest buffer capacities satisfying probabilistic constraints on waiting times. These results can be also applied to bounds of waiting times in more general systems. Numerical examples are also provided.

• Korean Journal of Acupuncture
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• v.23 no.2
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• pp.29-38
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• 2006

Objectives & Methods: This study was aimed to investigate denomination and distribution of fifteen main collaterals through oriental medicine literature. Results & Conclusions: 1. Kyung-maek-pyoun(經脈篇) of Yeong-chu (靈樞; divine pivot) says that fifteen main collaterals (十五絡脈) consist of main collaterals of the twelve regular meridians (十二經脈), Conception Channel (任孤), Governor channel (督脈) and great collateral of the spleen(脾之大絡). While chapter 26 of Nan-gyung(難經; Classic of difficulty) says that Yin-heel & Yang-heel channels are included instead of Conception channel(任脈) and Governor Channel (督脈). what is explained in Yeong-chu (靈樞; divine pivot) is considered more proper. 2. Great collateral of the stomach (胃之大絡 ) has been considered as one of the main collaterals, resulting in an opinion of sixteen main collaterals. We speculate that this is a wrong interpretation of Pyoung-in-gi-sang-lon(平人氣象論 ) of So-mun(素問). 3. Gumi (CV1) is more resonable than Hoeeum(CV14) for the Connecting point of Conception Channel(任脈) 4. Kyung-maek-pyoun (經脈篇) of Yeong-chu (靈樞; divine pivot) did not mention that the collateral of Hand Jueyin (手厥陰絡版) was running to Hand Shaoyang(手少陽經脈), which is considered to be omitted by mistake. 5. Fifteen main collaterals are mostly distributed on the legs and arms, while some are distributed in the internal organs, chest, abdomen, as well as head and five sensory organs.