• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.4
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• pp.311-318
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• 2016

The VTS concept was located as a principal methods of maritime safety administration in world's major harbors and expected to become the pivotal role for the future of the maritime and harbor society with e-Navigation epoch. If recent limelight concept of big-data has been included in aspect of information gathering and analysis with various studies, it's required advanced studies to improve the information analysis capability and application range of the data that can be mining by the VTS. In this study, contrast to other studies that aimed quantitative analysis as communication number, it can be mining the time information and each of the communication VTS for the target vessel, including qualitative analysis, such as the purpose or the type of communication. This comparison across multiple items of the collected information, and presenting the VTS data mining model (VCDF) that can be analyzed for the purpose of analyzing way, type and number of communication by ship's type, also number of violations through VTS communication. First, In Busan port case, it shows frequently information service and shows frequently communicating with particular types of vessels. Second, Passive VTS carried out notwithstanding many kinds of traffic violations due to communication congestion. This arranged information can be used as data for the analysis, as possible the level of traffic for VTSO situational awareness, which pointed to the 'workloads' in 'IALA Guideline' and could be used as a database for future research of e-Navigation.

• Journal of Biomedical Engineering Research
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• v.34 no.3
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• pp.148-155
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• 2013

This study is about the development of the wrist rehabilitation system for the patient who has limited capability of movement after stroke. Electromyography triggered training system (ETTS) can play the role between complete passive training and patient activating training system. Surface EMG was measured on pronator teres muscle and biceps brachii muscle for wrist pronation and supination. Our system detects whether the subject makes muscular effort for pronation or supination or nothing in every 50 ms. When the effort level exceeds the preset percentage of maximal voluntary contraction, the motor rotates according to the direction of the intention of the subject. EMG triggers the motor rotation for the wrist rehabilitation training until the preset angle. To evaluate its performance, the maximum voluntary contraction level was measured for 4 subjects at first. With the audio-visual instruction to rotate the wrist (pronation or supination) the subjects made effort to follow the instruction. After calculating root mean square (RMS) for 50 ms, the controller determines whether there was muscular effort to rotate while holding the motor. When there was an effort to rotate, the controller rotates the motor 0.8 degree. By comparing the RMS values from two channels of EMG, the controller determines the rotational direction. The onset delay is $0.76{\pm}0.24$ s and offset delay is $0.65{\pm}0.22$ s for pronation. For supination the onset delay is $1.24{\pm}0.41$ s and offset delay is $0.77{\pm}0.22$ s. The system responded fast enough to be used for rehabilitation training. The controller perceived the direction of rotation 100% correctly for the pronation and 97.5% correctly for supination. ETTS was developed and the fundamental functions were validated for normal subjects. The clinical validation should be done with patients for real world application. With ETTS, the subjects can train voluntarily over the limitation of the range of motion which increases the effectiveness of the rehabilitation training.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.5867-5874
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• 2012

The aim of this study was to find on muscle architectural and tissue compliance of biceps brachii in stroke patient based on elbow joint angle. The subjects of this study were twelve hemiplegic adults after stroke with passive range of motion in the elbow from $10^{\circ}$ to $90^{\circ}$ and Modified Ashworth Scale score 1 to 3 were recruited. Ultrasonography and Myotonometer was used to measure biceps brachii muscle pennation angle, fascicle length, and tissue compliance at the rest condition and pennation angle, fascicle length, and tissue compliance of the biceps brachii muscle were measured in the affected and unaffected sides of people after stroke at 9 different elbow angles ranging from $10^{\circ}$ to $90^{\circ}$ at the rest condition. The results of this study, comparisons found that the pennation angles of the affected biceps brachii muscle were significantly larger(p<.05) than the unaffected muscle in the most extended positions($<40^{\circ}$), whereas the affected fascicle lengths were significantly shorter(p<.05) than the unaffected muscle in most flexed positions($>20^{\circ}$), and the affected tissue compliance were significantly lower(p<.05) than the unaffected muscle in most extended positions($<50^{\circ}$) Therefore, pennation angles, fascicle lengths, and tissue compliance were found to be joint-angle-dependent in both the affected and unaffected sides at the rest condition. Suggest that, the results data can be used as a muscle architectural changes and clinical treatment research in stroke patients.

• The Korean Journal of Pharmacology
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• v.18 no.2
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• pp.89-102
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• 1982

The $Na^+-and\;K^+-induced\;Ca^{++}$ release was measured isotopically by millipore filter technique in pig heart mitochondria. With EGTA-quenching technique, the characteristics of mitochondrial $Ca^{++}-pool$ and the sources of $Ca^{++}$ released from mitochondria by $Na^+\;or\;K^+$ were analyzed. The mitochondrial $Ca^{++}-pool$ could be distinctly divided into two components: internal and external ones which were represented either by uptake through inner membrane, or by energy independent passive binding to external surface of mitochondria, respectively. In energized mitochondria, a large portion of $Ca^{++}$was transported into internal pool with little external binding, while in de-enerigzed state, a large portion of transported $Ca^{++}$ existed in the external pool with limited amount of $Ca^{++}$ in the internal pool which was possibly transported through the $Ca^{++}-carrier$ present in the inner membrane. $Na^+$ induced the $Ca^{++}$ release from both internal pool and external pool and external binding pool of mitochondria. In contrast, $K^+$ did not affect $Ca^{++}$ of the internal pool, but, displaced $Ca^{++}$ bound to external surface of the mitochondria. When the $Ca^{++}-reuptake$ was blocked by EGTA, the $Ca^{++}$ release from the internal pool by $Na^+$ was rapid; the rate of $Ca^{++}-efflux$ appeared to be a function of $[Na^+]^2$ and about 8mM $Na^+$ was required to elicit half-maximal velocity of $Ca^{++}-efflux$. So it was revealed that $Ca^{++}-efflux$ velocity was particulary sensitive to small changes of the $Na^+$ concentration in physiological range. Energy independent $Ca^{++}-binding$ sites of mitochondrial external surface showed unique characteristics. The total number of external $Ca^{++}-binding$ sites of pig heart mitochondria was 29 nmoles per mg protein and the dissociation constant(Kd) was $34{\mu}M$. The $Ca^{++}-binding$ to the external sites seemed to be competitively inhibited by $Na^+\;and\;K^+$; the inhibition constant(Ki) were 9.7 mM and 7.1 mM respectively. Considering the intracellular ion concentrations and large proportion of $Ca^{++}$ uptake in energized mitochondria, the external $Ca^{++}-binding$ pool of the mitochondria did not seem to play a significant role on the regulation of intracellular free $Ca^{++}$ concentration. From this experiment, it was suggested that a small change of intracellular free $Na^+$ concentration might play a role on regulation of free $Ca^{++}$ concentration in cardiac cell by influencing $Ca^{++}-efflux$ from the internal pool of mitochondria.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.79-85
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• 2017

It is critical that passengers should be given timely and correct escape or evacuation guidance from captain and crews when there are hazardous situations in a ship. Otherwise the consequences could be disastrous as "SEWOL Ferry" the South Korean passenger ship which sank in southern coastal area on 16th April 2014. Due to the captain's delayed evacuation decision and lack of sufficient number of crews to guide passengers' evacuation, the accident recorded many casualties, most of whom were high school students (302 passengers sank down with the ship while 172 rescued). Building a passenger ship with well-designed physical escape routes is one thing and guiding passengers to those escape routes in real disaster situation is another. Passengers get panic and move to a wrong direction, bottleneck makes situation worse, and even crews get panic also - passive static escape route signage and small number of trained crews might not be enough to take care of them. SESS (Smart Escape Support System) is being developed sponsored by South Korea Ministry of Ocean and Fisheries starting from 2016 with 4 years of roadmap. SESS comprises multiple active dynamic signage devices which communicate with real-time escape routing server software via LoRa (Long Range) proprietary wireless network.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.62-71
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• 2013

The passive emitter location method using TDOA and FDOA measurements has higher accuracy comparing to the single TDOA or FDOA based method. Moreover, it is able to estimate the velocity vector of a moving platform. Recently, several non-iterative methods were suggested using the nuisance parameter but the common reference sensor is needed for each pair of sensors. They show also relatively low performance in the case of a long range between the sensor groups and the emitter. To solve this, we derive the estimation method of the position and velocity of a moving platform based on the Gauss-Newton method. In addition, to analyze the estimation performance of the position and velocity, respectively, we decompose the CRLB matrix into each subspace. Simulation results show the estimation performance of the derived method and the CEP planes according to the given geometry of the sensors.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.11
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• pp.63-70
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• 2001

We demonstrate the MMIC (monolithic microwave integrated circuit) frequency doublers generating stable and low-cost 29 GHz local oscillator signals from 14.5 GHz input signals. These devices were designed and fabricated by using the M MIC integration process of $0.1\;{\mu}m$ gate-length PHEMTs (pseudomorphic high electron mobility transistors) and passive components. The measurements showed S11 or -9.2 dB at 145 GHz, S22 of -18.6 dG at 29 GHz and a minimum conversion loss of 18.2 dB at 14.5 GHz with an input power or 6 dBm. Fundamental signal of 14.5 GHz were suppressed below 15.2 dBe compared to the second harmonic signal at the output port, and the isolation characteristics of fundamental signal between the input and the output port were maintained above :i0 dB in the frequency range 10.5 GHz to 18.5 GHz. The chip size of the fabricated MMIC frequency doubler is $1.5{\times}2.2\;mm^2$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.10
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• pp.45-52
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• 2008

We investigated the design of an RF-powered, wireless temperature sensor tag chip using $0.18-{\mu}m$ CMOS technology. The transponder generates its own power supply from small incident RF signal using Schottky diodes in voltage multiplier. Ambient temperature is measured using a new low-power temperature-to-voltage converter, and an 8-bit single-slope ADC converts the measured voltage to digital data. ASK demodulator and digital control are combined to identify unique transponder (ID) sent by base station for multi-transponder applications. The measurement of the temperature sensor tag chip showed a resolution of $0.64^{\circ}C/LSB$ in the range from $20^{\circ}C$ to $100^{\circ}C$, which is suitable for environmental temperature monitoring. The chip size is $1.1{\times}0.34mm^2$, and operates at clock frequency of 100 kHz while consuming $64{\mu}W$ power. The temperature sensor required a -11 dBm RF input power, supported a conversion rate of 12.5 k-samples/sec, and a maximum error of $0.5^{\circ}C$.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.103-105
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• 2003

After fifteen years of development, Magnetic Resonance (MR) technology for human imaging and spectroscopy is reaching a refined state with FDA approved 3T clinical products from Siemens, GE, and Philips. Broker has cleared CE approval with a 4T system. Varian supports a 4T system platform as well. Shielded magnets are standard at 3T from GE, Oxford, Magnex, and IGC. A shielded 4T whole body magnet is available from Oxford. Stronger switched gradients and dynamic shim coils, desired at any field, areespecially useful at higher static magnetic fields B0. In addition to the higher currents required for higher resolution slice or volume selection afforded by higher SNR, whole body gradient coils will be driven at increasing slew rates to meet the needs of new cardiac applications and other requirements. For example 3T and 4T systems are now being equipped with 2kV, 500A gradient coils and amplifiers capable of generating 4G/cm in 200msec, over a 67+/-cm bore diameter. High field EPI applications require oscillation rates at 1 kHz and higher. To achieve a benchmark 0.2 ppm shim over a 30cm sphere in a high field magnet, at least four stages of shimming need to be considered. 1) A good high field magnet will be built to a homogeneity spec. falling in the range of 100 to 150 ppm over this 30cm spherical "sweet spot" 2) Most modern high field magnets will also have superconducting shim coils capable of finding 1.5 ppm by their adjustment during system installation. 3) Passive ferro-magnetic shimming combined with 4) active, high order room temperature shim coils (as many as five orders are now being recommended) will accomplish 0.2 ppm over the 30cm sphere, and 0.1 ppm over a human brain in even the highest field magnets for human studies. Safety concerns for strong, fast gradients at any B0 field include acoustic noise and peripheral nerve stimulation. One or more of the mechanical decoupling methods may lead to quieter gradients. Patient positioning relative to asymmetric or short gradient coils may limit peripheral nerve stimulation at higher slew rates. Gradient designs combining a short coil for local speed and strength with a longer coil for coverage are being developed for 3T systems. Local gradients give another approach to maximizing performance over a limited region while keeping within the physiologically imposed dB0/dt performance limits.

• Journal of Korean Foot and Ankle Society
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• v.15 no.2
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• pp.51-57
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• 2011

Pilon fractures involving distal tibia remain one of the most difficult therapeutic challenges that confront the orthopedic surgeons because of associated soft tissue injury is common. To introduce and describe the diagnosis, current treatment, results and complications of the pilon fractures. In initial assessment, the correct evaluation of the fracture type through radiographic checkup and examination of the soft tissue envelope is needed to decide appropriate treatment planning of pilon fractures. Even though Ruedi and Allgower reported 74% good and excellent results with primary open reduction and internal fixation, recently the second staged treatment of pilon fractures is preferred to orthopedic traumatologist because of the soft tissue problem is common after primary open reduction and internal fixation. The components of the first stage are focused primarily on stabilization of the soft tissue envelope. If fibula is fractured, fibular open reduction and internal fixation is integral part of initial management for reducing the majority of tibial deformities. Ankle-spanning temporary external fixator is used to restore limb alignment and displaced intraarticular fragments through ligamentotaxis and distraction. And the second stage, definitive open reduction and internal fixation of the tibial component, is undertaken when the soft tissue injury has resolved and no infection sign is seen on pin site of external fixator. The goals of definitive internal fixation should include absolute stability and interfragmentary compression of reduced articular segments, stable fixation of the articular segment to the tibial diaphysis, and restoration of coronal, transverse, and sagittal plane alignments. The location, rigidity, and kinds of the implants are based on each individual fractures. The conventional plate fixation has more advantages in anatomical reduction of intraarticular fractures than locking compression plate. But it has more complications as infection, delayed union and nonunion. The locking compression plate fixation provides greater stability and lesser wound problem than conventional implants. But the locking compression plate remains poorly defined for intraarticular fractures of the distal tibia. Active, active assisted, passive range of motion of the ankle is recommended when postoperative rehabilitation is started. Splinting with the foot in neutral is continued until suture is removed at the 2~3 weeks and weight bearing is delayed for approximately 12 weeks. The recognition of the soft tissue injury has evolved as a critical component of the management of pilon fractures. At this point, the second staged treatment of pilon fractures is good treatment option because of it is designed to promote recovery of the soft tissue envelope in first stage operation and get a good result in definitive reduction and stabilization of the articular surface and axial alignment in second stage operation.