• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.6
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• pp.716-722
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• 2012

In this paper, we analyzed the RF interactions between WWAN antennas and an LCD driving module inside the cover of a notebook computer, and discussed reduction method of RF coupling. In order to simulate the RF noise source from the LCD driving module, a multi-band antenna was designed and used with a simplified notebook model to test the RF coupling phenomena. We verified that the RF noise coupling is enhanced at certain frequencies due to cavity structure formed inside the notebook computer. Also, we showed that conductive barrier walls, which are inserted inside the notebook, could be effective in reducing RF coupling.

• Journal of the Korean Society of Radiology
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• v.6 no.5
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• pp.415-419
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• 2012

Frozen shoulder was diagnosed with this study 14 patients were enrolled. Patients who volunteer to visit the configuration is more than six months and pain were studied in a chronic illness. Frozen shoulder to patients based on these results the effect of KTO treatment is a diet that is valid for a unified model and the exact effect can be enhanced, be combined with other treatments and therapies are deemed necessary. When applied to patients with Frozen shoulder KTO with an increased range of motion of the shoulder can result in a reduction of pain.

• Membrane Journal
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• v.22 no.6
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• pp.481-488
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• 2012

The anionic exchange polymer, poly(vinyl amine)(PVAm), was coated onto polyamide (PA) reverse osmosis (RO) membranes by using 'salting-out' method. The effects of the fouling phenomena for these PVAm coated membranes were investigated using the model foulants, bovine serum albumin (BSA), humic acid (HA), and sodium alginate (SA). The surface coating and the fouling phenomena were observed by the scanning electron microscopy. And the flux was measured for each 100 ppm of above foulant aqueous solution at the operating pressure, 2, 4, 8 bar. The PVAm-coated PA membranes showed somewhat fouling improvements and the fouling reduction was shown in the order of HA > SA > BSA, particularly HA case was distinct.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5343-5364
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• 2016

Considering the tradeoff between energy consumption and outage behavior in buffer-aided relay selection, a novel energy-efficient buffer-aided optimal relay selection scheme with power adaptation and Inter-Relay Interference (IRI) cancellation is proposed. In the proposed scheme, energy consumption minimization is the objective with the consideration of relay buffer state, outage probability and relay power control, in order to eliminate IRI. The proposed scheme selects a pair of optimal relays from multiple candidate relays, denoted as optimal receive relay and optimal transmit relay respectively. Source-relay and relay-destination communications can be performed within a time-slot, which performs as Full-Duplex (FD) relaying. Markov chain model is applied to analyze the evolution of relay buffer states. System steady state outage probability and achievable diversity order are derived respectively. In addition, packet transmission delay and power reduction performance are investigated with a specific analysis. Numerical results show that the proposed scheme outperforms other relay selection schemes in terms of outage behavior with power adaptation and IRI cancellation in the same relay number and buffer size scenario. Compared with Buffer State relay selection method, the proposed scheme reduces transmission delay significantly with the same amount of relays. Average transmit power reduction can be implemented to relays with the increasing of relay number and buffer size, which realizes the tradeoff between energy-efficiency, outage behavior and delay performance in green cooperative communications.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.3
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• pp.68-73
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• 2014

Research is being carried out at Korea Aerospace Research Institute with aim of design a HALE UAV(High Altitude Long Endurance Unmanned Air Vehicle). HALE UAVs are ideally suited to provide surveillance, remote sensing and communication relay capabilities for both military and civilian applications. HALE UAVs typically cruise at an altitude between 15 km and 20 km, travelling at low speed and circling specific area of interest. Airframe structural point of view, weight reduction of the airframe structure is the most important method to improve the flight efficiency. High modulus CFRP(Carbon Fiber Reinforced Polymer) has been used in designing the structure in order to minimize the airframe weight. With respect to structural design and analysis, the key question is to decide an adequate airworthiness certification base to define suitable load cases for sizing of various structural components. In this study, FAR(Federal Aviation Regulation) 23 have constituted the guidance and benchmark throughout all structural studies. And the MSC/FlightLoads was introduced to analyze the flight loads for the HALE UAV. The MSC/FlightLoads can compute the flexible air load and analyzed loads are distributed on structural model directly. A preliminary structural concept was defined in accordance with the estimated inertial and aerodynamic loads. A FEM analysis was carried out using the MSC/Nastran code to predict the static and dynamic behaviour of UAV structure.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.165-175
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• 2021

As the advent of the Fourth Industrial Revolution and Information Age, companies are in the state of infinite competition due to the rapidly changing technological environment and fierce competition. In this situation companies are making efforts to gain the competitive advantage by introducing information systems. Supply Chain Management (SCM) is considered a method to gain a competitive edge in rapid change. In fact, companies that already have introduced the SCM system are achieving company renovation with positive effects such as increase of sales stock reduction on-time delivery cost reduction and improved efficiency. This study was started to investigate the resistance that occurs in introducing the SCM system for small and medium-sized manufacturing industries that have not yet introduced the SCM system despite the importance of the SCM system, and to check the effect on the intention of the introduction. As the result of this study, the first is that the company has the higher technological innovation, the more positive the effect on Relative advantage Compatibility Perceived risk, Complexity. Second, The compatibility of the SCM system was rejected in innovation resistance, but it is adopted with the highest impact in the introduction intention. In addition, the mediating effect of innovation resistance was also rejected, confirming that if the SCM system is compatible for the company, it doesn't affect the resistance and is the biggest factor to consider in the introduction of the SCM system. Third, the perceived risk of the SCM system doesn't directly affect the intention to introduce, but has an indirect effect when mediation innovation resistance.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.6
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• pp.290-302
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• 2022

In this study, it was examined for the reduction of wave overtopping and water level fluctuation in front of the revetment when applying a reinforcement method to revetment where wave overtopping occurs. As a result of the study, in the case of the cross-sectional experiment. more than 70% of the wave overtopping reduction effect depending on the reinforcement conditions was occurred, and it was analyzed that the result increases by about four times or more in the comparison with the 3d test. The average water level in front of the revetment was lowered when a low crest structure was not installed. and there was a tendency to rise under the condition of low crest structures installed. In the comparison with the wave basin test, there was a difference of about 0.5 to 0.6 times when a low crest structure was not installed, and it was increased by 5.5 times after low crest structures were installed.

• Journal of KIISE
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• v.44 no.1
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• pp.44-50
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• 2017

Pedestrian detection, an important component of autonomous driving and driving assistant system, has been extensively studied for many years. In particular, image based pedestrian detection methods such as Hierarchical classifier or HOG and, deep models such as ConvNet are well studied. The evaluation score has increased by the various methods. However, pedestrian detection requires high sensitivity to errors, since small error can lead to life or death problems. Consequently, further reduction in pedestrian detection error rate of autonomous systems is required. We proposed a new method to detect pedestrians and reduce the error rate by using the Faster R-CNN with new developed pedestrian training data sets. Finally, we compared the proposed method with the previous models, in order to show the improvement of our method.

• Journal of Digital Convergence
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• v.11 no.6
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• pp.169-174
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• 2013

Speech recognition, the problem of performance degradation is the difference between the model training and recognition environments. Silence features normalized using the method as a way to reduce the inconsistency of such an environment. Silence features normalized way of existing in the low signal-to-noise ratio. Increase the energy level of the silence interval for voice and non-voice classification accuracy due to the falling. There is a problem in the recognition performance is degraded. This paper proposed a robust speech detection method in noisy environments using a silence feature normalization and voice energy maximize. In the high signal-to-noise ratio for the proposed method was used to maximize the characteristics receive less characterized the effects of noise by the voice energy. Cepstral feature distribution of voice / non-voice characteristics in the low signal-to-noise ratio and improves the recognition performance. Result of the recognition experiment, recognition performance improved compared to the conventional method.

• Structural Engineering and Mechanics
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• v.37 no.6
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• pp.671-684
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• 2011

Deciding on an optimal sensor placement (OSP) is a common problem encountered in many engineering applications and is also a critical issue in the construction and implementation of an effective structural health monitoring (SHM) system. The present study focuses with techniques for selecting optimal sensor locations in a sensor network designed to monitor the health condition of Dalian World Trade Building which is the tallest in the northeast of China. Since the number of degree-of-freedom (DOF) of the building structure is too large, multi-modes should be selected to describe the dynamic behavior of a structural system with sufficient accuracy to allow its health state to be determined effectively. However, it's difficult to accurately distinguish the translational and rotational modes for the flexible structures with closely spaced modes by the modal participation mass ratios. In this paper, a new method of the OSP that computing the mode shape matrix in the weak axis of structure by the simplified multi-DOF system was presented based on the equivalent rigidity parameter identification method. The initial sensor assignment was obtained by the QR-factorization of the structural mode shape matrix. Taking the maximum off-diagonal element of the modal assurance criterion (MAC) matrix as a target function, one more sensor was added each time until the maximum off-diagonal element of the MAC reaches the threshold. Considering the economic factors, the final plan of sensor placement was determined. The numerical example demonstrated the feasibility and effectiveness of the proposed scheme.