• Journal of the Institute of Convergence Signal Processing
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• v.16 no.3
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• pp.115-121
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• 2015

A device which could cut off the consumption of standby power by electric or electronic devices at homes and offices while waiting for a command to carry out the main functions from the inside or the outside was developed at a low price. Efforts to save standby power have been made on a global scale as well as by advanced countries. The consumption of standby power in South Korea is also increasing gradually due to increasing trend in the number of electronic and electric devices per household, becoming a major factor for waste of electric energy. The previous standby power cutoff devices themselves have high electric energy consumption and complicated structures, making the purpose less meaningful. Therefore, a low-priced standby power cutoff device is suggested in this study, which compensates such problems and cuts off the consumption of standby power completely. The circuit of the suggested standby power cutoff device was designed and implemented by applying it to an earth leakage breaker and an (electrical) outlet. Experimental results show its superiority.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.4
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• pp.178-184
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• 2005

In this paper, using diplexer structure and varactor diode controlled by reverse bias voltage for diplexer switch gives possibilities to improve isolation and current characteristics. 1 have newly designed switch with high isolation by application varactor diode corresponding to capacitor of diplexer. The low-pass filter for proposed tunable diplexer passes the microwave signal in the bandwidth for wireless cellular network systems and high-pass filter passes it in the bandwidth for wireless personal communication services (PCS) network systems. As the capacitance of the low-pass filter increases, the cut-off frequency can be moved to low frequency, so that the switch is on state in cellular bandwidth and off state in the PCS bandwidth, in contrast to, as the capacitance for attenuation characteristic of high-pass filter increases, it can be moved to high frequency, so that the switch is off state and on state in the cellular bandwidth. it is possible to improve isolation and current consumption characteristics by application diplexer design methods and varactor diode. 1 expect that the tunable diplexer circuit and design methods should be able to find applications on MMIC and low temperature copired ceramic (LTCC).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.4
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• pp.399-422
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• 2009

Although current wireless mesh network (WMN) applications experience a perceptually uninterrupted hand-off, their throughput after the hand-off event may be significantly degraded due to the low available bandwidth of the mobile client's new master. In this paper, we propose a novel mobility management scheme for 802.11-based WMNs that enables both seamless hand-off for transparent communications, and bandwidth awareness for stable application performance after the hand-off process. To facilitate this, we (i) present a new buffer moment in support of the fast Layer-2 hand-off mechanism to cut the packet loss incurred in the hand-off process to zero and (ii) design a dynamic admission control to grant joining accepts to mesh clients. We evaluate the benefits and drawbacks of the proposal for both UDP and TCP traffic, as well as the fairness of the proposal. Our results show that the new scheme can not only minimize hand-off latency, but also maintain the current application rates of roaming users by choosing an appropriate new master for joining.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.4
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• pp.89-95
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• 2005

Thrust cut off(TCO) system is installed at the port of a rocket motor case forward dome. The snap ring and the closure are escaped sequentially by pulling out a wedge under internal pressure. The hydraulic structural tests of TCO and numerical simulations were performed, and both results were compared to understand the deformation behavior of TCO. By increasing splines symmetrically, the sealing capacity of TCO can be improved significantly. The escape pressure of TCO increases according to the increase of friction coefficient and there is a critical friction coefficient beyond which the snap ring can not be nearly escaped even after forced escape of wedge. Under low friction coefficient the snap ring is contracted to radial direction and easily escaped. But, under high friction coefficient, the snap ring can not be escaped from the port even after severe plastic deformation.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.3
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• pp.87-93
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• 2015

PURPOSE: The purpose of this study was to investigate the effects of the 8.5seconds cut-off of the 8-foot up-and-go test as a predictor of falling and a good discriminator of fallers and non-fallers in women in their 60s to 80s. METHODS: The final subjects of this study were 98 elderly women from six senior centers of B metropolitan city. The 8-foot up-and-go test evaluated agility and dynamic balance. The chair-stand test measured the muscle strength for of the lower body. Ankle dorsiflexion and plantar flexion were measured to assess the ankle mobility of the subjects in this study. RESULTS: The below 8.5seconds group showed significantly low values in age and high values in chair-stand (times/30 s), plantar flexion ($^{\circ}$), and K-MMSE (score) compared to the over 8.5seconds group. This group was significantly faster compared to the over 8.5seconds group. In the below 8.5seconds group, only plantar flexion ($^{\circ}$) of all the items showed significantly higher values among those in their 60s compared to those in their 70s and 80s. CONCLUSION: The 8.5seconds cut-off on the 8-foot up-and-go test as a good discriminator and predictor of falling showed differences among fall risk factors (age, lower extremity strength, cognition, and ankle mobility) in women in their 60s to 80s without having regular exercise and a fall experience over the past ones year.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.396-397
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• 2011

This paper has proposed a multi-channel low pass filter (LPF) for LTE-Advanced systems. The proposed LPF is an active-RC 5th chebyshev topology with three cut-off frequencies of 5 MHz, 10 MHz, and 40 MHz. A 3-bit tuning circuit has been adopted to prevent variations of each cut-off frequency from process, voltage, and temperature (PVT). To achieve a high cut-off frequency of 40 MHz, an operational amplifier used in the proposed filter has employed a PMOS cross-connection load with a negative impedance. A proposed filter has been implemented in a $0.13-{\mu}m$ CMOS technology and consumes 20.2 mW with a 1.2V supply voltage.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.466-471
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• 2017

SOTM is a device for the satellite communication on the move. Many studies are conducted on microstrip, waveguide and array antenna for the low profile of the SOTM's antenna. But those antennas have a problem that is difficult to adjust the polarization, and for that reason we have studied the parabolic antenna structure. The general form of parabolic reflector structure is circular, but we used cut-off shape reflector by cutting the upper and lower reflector for low profile antenna. Accordingly, this results in the decrease of reflector area which causes reduced gain and G/T ratio. In order to solve this problem, we have transformed and designed the sub reflector for improving the efficiency and gain of the cut- off shape parabolic antenna.

• The Journal of the Korea Contents Association
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• v.19 no.12
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• pp.527-534
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• 2019

Most of the prints left on the crime scene are latent prints. And, even after the latent prints have been developed, additional enhancement is required and forensic light sources are mainly used. Depending on the applied technique and the light source used, it is difficult to obtain the ideal enhancement effect when the reflected light cannot be cut off well. In this study, we improved the wavelength of the forensic light source by attaching a low-pass filter, resulting in better quality fingerprint images.

• Korean Circulation Journal
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• v.53 no.9
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• pp.635-644
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• 2023

Background and Objectives: The History, Electrocardiography, Age, Risk factors, and Troponin (HEART) pathway was developed to identify patients at low risk of a major adverse cardiac event (MACE) among patients presenting with chest pain to the emergency department. Methods: We modified the HEART pathway by replacing the Korean cut-off of 25 kg/m² with the conventional threshold of 30 kg/m² in the definition of obesity among risk factors. The primary outcome was a MACE within 30 days, which included acute myocardial infarction, primary coronary intervention, coronary artery bypass grafting, and all-cause death. Results: Of the 1,304 patients prospectively enrolled, MACE occurred in 320 (24.5%). The modified HEART pathway identified 37.3% of patients as low-risk compared with 38.3% using the HEART pathway. Of the 500 patients classified as low-risk with HEART pathway, 8 (1.6%) experienced MACE, and of the 486 low-risk patients with modified HEART pathway, 4 (0.8%) experienced MACE. The modified HEART pathway had a sensitivity of 98.8%, a negative predictive value (NPV) of 99.2%, a specificity of 49.0%, and a positive predictive value (PPV) of 38.6%, compared with the original HEART pathway, with a sensitivity of 97.5%, a NPV of 98.4%, a specificity of 50.0%, and a PPV of 38.8%. Conclusions: When applied to Korean population, modified HEART pathway could identify patients safe for early discharge more accurately by using body mass index cut-off levels suggested for Koreans.

• The Korean Journal of Food And Nutrition
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• v.20 no.3
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• pp.295-303
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• 2007

As a result of life-style changes, consumer's concerns of food have shifted from calories and nutrition to health and convenience. Fresh-cut products are one such new direction for fruit and vegetable consumption. In this study, the vitamin C, mineral, and pesticide contents of various fresh-cut products were analyzed. According to sensory evaluations, the key reason for a lower than expected overall acceptability of many fresh-cut products is that they are likely to have browning and can easily lose their freshness. Also, the sensory evaluation showed that shriveling, the degree of browning, softening around the cut edge, and off-flavors were the primary factors affecting the quality of fresh-cut products. As a nutritional factor of quality, vitamin C content was not practical with regard to fresh-cut lettuce because the level was very low. For product safety, residual pesticides were detected in the fresh-cut products, but the results showed that all items were under permitted levels and considered safe. In evaluation of the microbial levels of the fresh-cut market products, the levels of viable cells, mold, yeast, coliform bacteria, and enterobacteriaceae were not significantly different based on the summer and winter seasons. The levels of S. aureus and Listeria spp. in the products were higher during the summer season than the winter.