• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.3
• /
• pp.83-92
• /
• 2018

This paper uses the Apollonius Circle technique to estimate the position of a target that generates a specific signal by using a drone, which is rapidly becoming a rapidly expanding industry. The existing direction finding method is performed through the vehicle on the ground or installed the antenna at a high position to detect the position of the target. However, the conventional direction finding method is difficult to configure the reception environment of the LOS signal, It is difficult. However, the direction finding using the drone is easy to construct and measure the LOS signal receiving environment using the drone flying at high altitude. In this study, we use the 3D 800MHz Path-Loss Model to reconstruct the signal by using the measurement data of the ground direction finding, reconstruct the signal by using the 3-D 800MHz Path-Loss Model, and use the Apollonius Circle method to estimate the position of the target. A simulation was performed to estimate the position of the target. Simulation was performed to determine the target position estimation performance by configuring the ground direction finding and the dron direction finding.

• 한국HCI학회:학술대회논문집
• /
• 2008.02a
• /
• pp.163-167
• /
• 2008

This paper presents the analysis of tactile effects on different body parts according to the various vibration patterns. The experiments use a vibration pad made of 16 vibration elements in the form of $4{\times}4$ array. The vibration elements are controlled by a 8-bit microprocessor. The sound of gunshot initiates a vibration pattern on different body parts and its sensitivity is measured. The analysis of the experiments lead us to conclude that the vibration pad is the most realistic interface for shooting games and the shoulder part is the most sensitive part in the body. In addition, the most effective vibration pattern is the for the pattern which gives the sensation of spreading out from the center to the outside. This study analyzes the relationship between the human body parts and the tactile sensations by the various vibration patterns. The result of this study will be a good reference for user studies in the field of haptics based on the vibration.

• Journal of The Korean Association For Science Education
• /
• v.22 no.1
• /
• pp.204-213
• /
• 2002

In this study, the students' responses on the items of chemistry II in the College Scholastics Ability Test (CSAT) implemented for the past 3 years since 1999 was investigated. The number of applicants and mean score of chemistry II, average percent correct by contents and inquiry process, and the items with high and/or low percent correct are analysed and discussed. The percentage of applicants for natural science track is reduced each year. However, more than 25% of natural science track applied to chemistry II, which ranked second to biology II. The mean score of chemistry II was increased in 2001 along with those of other subjects. There is no difference in average percent correct either by contents or inquiry process. Students performed generally poor at solving test items relating to 'colligative properties of solution' such as 'boiling point elevation' or 'osmotic pressure', and very well at solving test items relating to 'reaction rates'. Educational implications are discussed.

• The Journal of the Korean bone and joint tumor society
• /
• v.6 no.2
• /
• pp.106-111
• /
• 2000

Focal fibrocartilaginous dysplasia(FFCD) is an uncommon, benign condition associated with unilateral tibia vara among young children. FFCD has a typical plain radiographic finding, which has a concave radiolucent defect in the metadiaphyseal junction of medial aspect of the proximal tibia. The varus deformity occurs at the site of the lesion. Spontaneous remodeling and resolution of bony defect may be expected, but the corrective osteotomy may also be needed in some cases. The authors described a case of unilateral tibia vara caused by FFCD, diagnosed by excisional biopsy and treated with dome-shaped proximal tibial osteotomy and bone graft.

• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.3
• /
• pp.292-297
• /
• 2015

In this paper, we reported the bypass unit for ship area networks in order to detour the communication failure regions and poor communication links. The device was composed of three parts of circuits for power cut-off, protection, and coupling transformer. Since the coupling transformer exerts a dominant influence on the performance of the by-pass unit, we have tried to find the optimal magnetic core materials and its dimensions. The prototype was passed through the performance test of insertion loss, temperature, and vibration characteristics. The insertion loss was around -2 dB in the range of 90 kHz ~ 30 MHz and the average communication speed was 59.2 Mbps in the laboratory. A pilot communication test using the developed tool was conducted in the training ship of the Korea Maritime and Ocean University. As a results of experiment, we showed that the wired communication among the heterogeneous-links in the ship area networks are possible by the bypass unit and also a high speed communication services are available in ~ Mbps by using a power-line.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.7
• /
• pp.923-928
• /
• 2014

Communication underwater is severely limited when compared to communications in air because water is essentially opaque to electromagnetic radiation except in visible range. Acoustic systems are capable of long range communication, but offer limited data rates and significant latency due to the speed of sound in water. On the other hand, optical wireless communication has been proposed as one of the best alternatives to meet the requirements of the underwater observation and subsea monitoring systems. It will help In this study, we are developing an underwater optical communication system that integrates with a depot ship floating on the water. An interface between LED lighting communication system and Bluetooth module is presented to support the underwater-to-air communications. Error free image and text transmission at 3 m of water were achieved at bit rates of 230.4 kbps. This development effort will enhance infrastructure to efficiently interconnect between underwater wireless systems and command ship networks for underwater monitoring.

• Journal of Advanced Marine Engineering and Technology
• /
• v.37 no.4
• /
• pp.425-430
• /
• 2013

Robust and high speed underwater communication is severely limited when compared to communications in terrestial. In free space, RF communication operates over long distances at high data rates. However, the obstacle in seawater is the severe attenuation due to the conducting nature. Acoustic modems are capable of long range communication up to several tens of kilometers, but it has low data-rate, high power consumption and low propagation speed. An alternative means of underwater communication is based on optics, wherein high data rates are possible. In this paper, the characteristics of underwater channel in the range of visible wavelength is investigated. And the possibility of optical wireless communication in underwater is also described. The LED-based transceiver and CMOS sensor module are integrated in the system, and the performance of image transmission was demonstrated.

• Natural Product Sciences
• /
• v.10 no.6
• /
• pp.315-320
• /
• 2004

Alpha-viniferin was previously isolated as a cyclooxygenase (COX)-2 inhibitor from Carex humilis (Cyperaceae) and is an oligomeric stilbene compound with benzofuran (BF) moieties in its chemical structure. In the present study, a chemically synthetic BF compound, named as 3,3-dimethyl-2,3,4,6,7,8,9,10,11,12,13,14,15,16,17,18-hexadecahydro-1H-benzo[b] cyclopentadeca[d]furan-1-one, was discovered to inhibit bacterial lipo polysaccharide (LPS)-induced prostaglandin $E_2$ $(PGE_2)$ production in macrophages RAW 264.7. The BF compound exhibited a selectively preferred inhibitory effect on COX-2 activity over COX-1 activity. Furthermore, BF compound inhibited LPS-induced COX-2 expression at transcription level. As a down-regulatory mechanism of COX-2 expression shown by BF compound, suppression of nuclear factor $(NF)-{\kappa}B$ activation has been demonstrated. BF compound inhibited LPS-induced $NF-{\kappa}B$ transcriptional activity and nuclear translocation of $NF-{\kappa}B$ p65, in parallel, but did not affect LPS-induced degradation of inhibitory ${\kappa}B{\alpha}$ protein $(I{\kappa}B{\alpha})$. Taken together, anti-inflammatory effect of BF compound on $PGE_2$ production was ascribed by its down-regulatory action on LPS-induced COX-2 synthesis in addition to inhibitory action on enzyme activity of COX-2.

• The Journal of Internal Korean Medicine
• /
• v.35 no.1
• /
• pp.1-11
• /
• 2014

Objectives : To investigate the effects of Sa-am acupuncture on muscle architecture and elastic properties of the spastic elbow flexor and to evaluate the correlation between clinical findings and parameters of real-time sonoelastography (RTS) in patients with chronic post-stroke hemiparesis. Materials and Methods : Seven patients (five males, two females) with chronic post-stroke hemiparesis were included. Sa-am acupuncture of Ganseunggyeok (肝勝格: LU8 LR4 補, HT8 LR2 瀉) was applied to the unaffected side 3 times a week for 4 weeks. During each acupuncture treatment period, patients were requested to exercise their affected arm, and spasticity and functional recovery outcomes of the affected arm were evaluated before and after Sa-am acupuncture treatment. Clinical outcomes were assessed using motricity index (MI), modified Ashworth scale (MAS), Fugl-Meyer assessment scale (FMA) and modified Barthel index (MBI) for elbow flexor spasticity. RTS images indicate the relative hardness of the examined muscles ranged from red (hard) to purple (soft) for color-scale, and from black (hard) to white (soft) for hue scale. Color and hue histograms of the biceps brachii and brachialis were analyzed using Image J software, and median red, blue, and hue pixel intensity were obtained. Results : MI and FMA score significantly increased and MAS score significantly decreased (p<0.05). F-wave maximal amplitude of affected abductor pollicis brevis significantly decreased (p<0.05). Muscle thickness of affected brachialis significantly increased (p<0.05). Red and green pixel intensity of affected brachialis significantly decreased (p<0.05). Conclusions : Our study revealed that Sa-am acupuncture is effective as a useful and safe treatment for spasticity in chronic post-stroke hemiparesis.

• Journal of Oriental Neuropsychiatry
• /
• v.25 no.3
• /
• pp.287-296
• /
• 2014

Objectives: Alzheimer's Dementia is somewhat common in clinical stages, and there are many reports and papers regarding this subject. We explain the present state of Alzheimer's Dementia in JON (The Journal of Oriental Neuropsychiatry) for the benefits of clinical practice. Methods: We searched for articles in JON from 1990 to 2014 and selected ones that were related to Alzheimer's Dementia; then, we analyzed the data and placed it in four categories, like experimental study, case study, Clinical Data-Analysis study, and clinical trial. Results: 1) We found 47 articles relating to Alzheimer's Dementia in JON from 1997 to 2014: 41 experimental studies, 1 case study, 1 Clinical Data-Analysis study, and 4 Clinical trials. 2) There were Chung-kyung Acupuncture Method, Auricular acupuncture, and Cha-rak Acupuncture Method to treat Alzheimer's Dementia. 3) There were many additional treatments, like aroma therapy. 4) In the experimental study, they reported on several herbs, including herbal prescriptions that affected the suppression of related mRNAs and genes. 5) There were 4 clinical trials regarding herbal prescription that was effective for treating Alzheimer's Dementia. Conclusions: In JON, regarding Alzheimer's Dementia, the majority dealt with experimental studies. Therefore, we also have to expand our sight into other fields of study. We need more clinical trials and case studies for the treatment of Alzheimer's Dementia in Oriental Neuropsychiatry.