• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.89-97
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• 2012

In recent years, efficient energy management technologies are required, as environmental problems have emerged worldwide. In response to this, smart home services focused on efficient energy management technology seems to be emerging. And the integration of technology of user-oriented real-time energy monitoring and control systems is required. In this paper, we present a location-based green home service using smart phones for efficient energy management in a house. We design a green home network system to apply the green home service, and implement an integrated gateway system which connects and controls each appliance in a house. We develop appliance control services and indoor location services on smart phones, and determine whether user's occupancy of each room by measuring the location according to the variation of signal strength. In order to evaluate the performance of the energy savings, we have set up the scenarios of energy usage pattern and have compared the energy variation resulting from the application of the indoor location services with smart meters. A comparison of energy usage demonstrated that the energy saving of a house with the proposed location-based green home service was down up to 30%.

• Journal of Acupuncture Research
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• v.32 no.4
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• pp.147-156
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• 2015

Objectives : This study aims to evaluate the effectiveness and safety of Korean medicine for a thoracolumbar compression fracture. Methods : We searched six Korean databases (DBPIA, Korean Studies Information Service System, Oriental Medicine Advanced Searching Integrated System, National Digital Science Library, Research Information Sharing Service, KoreaMed) (up to June 2015) and the Journal of Korean Acupuncture and Moxibustion Society. Unpublished studies were also searched. Clinical research, other than case reports involving less than 10 patients, were eligible. The effectiveness and safety of Korean Medicine was analyzed. The 'Risk of Bias' was assessed using the 'Risk of Bias' assessment tool for non-randomized studies as well as the Cochrane Collaboration's 'Risk of Bias' tool. Results : We found 12 before-after studies (374 patients). There was no randomized trial. All studies combined at least three different types of Korean medicine treatments. The period of treatment varied between less a week and 154 days. All the included studies reported improvements in pain, functional disability related to lower back pain, global assessment, and benefits in the compression ratio of a fractured vertebrae and skin temperature measured by digital infrared thermal imaging in comparison with the baseline. However, all studies had a high risk of bias and three studies reported mild adverse events. Conclusions : There is no randomized trial for the role of Korean medicine for patients with a thoracolumbar compression fracture. The effectiveness and safety of Korean medicine for this population remains unclear. Findings in this review are seriously biased due to observational design and a high risk of bias included in the studies. Future high-quality randomized trials are warranted.

• Journal of the Korean Geosynthetics Society
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• v.14 no.1
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• pp.1-10
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• 2015

Recently, several researches on the development of new economical anchor systems have been performed to support floating structures. This study focused on the group suction piles, which connect mid-sized suction piles instead of a single suction pile with large-diameter. The group suction pile shows the complex bearing behavior with translation and rotation, so it is difficult to apply conventional design methods. Therefore, the numerical modeling technique was developed to evaluate the horizontal bearing capacity of the group suction piles in clay. The technique models suction piles as beam elements and soil reaction as non-linear springs. To analyze the applicability of the modeling, the horizontal load-movement curves of the proposed modeling were compared with those of three-dimensional finite element analyses. The comparison showed that the modeling underestimates the capacity and overestimate the displacement corresponding to the maximum capacity. Therefore, the correction factors for the horizontal soil resistance was proposed to match the bearing capacity from the three-dimensional finite element analyses.

• Journal of the HCI Society of Korea
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• v.1 no.2
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• pp.19-26
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• 2006

This paper presents a novel pneumatic tactile display that can deliver some useful information. The air-jet display forms 5 by 5 arrays and features air nozzles with an external diameter of 2.4mm and internal diameter of 1.5 mm. In comparison with other tactile displays such as vibrotactile, there is little concrete psychophysical data relating to pneumatic displays, a fact which hinders their adoption. This paper addresses this challenge, and presents brief psychophysical studies examining localization rate, the two point threshold, stimulus intensity and the temporal threshold of cues produced by pneumatic air jets. Two groups of subjects were used in these studies, subsequently termed groups A and B. Both were comprised of eight participants. In the case of localization study we obtained 58.13% and 85.9% of localization rates each for dense display and sparse display. Two-points threshold test showed the length of gap between two air-jet stimuli which subjects can detect. However, it was formidable to find out precise temporal resolution of PTI owing to the limitation of capability of the pneumatic valves. Lastly, the results of stimulus intensity study suggest that by varying the size of a pneumatically created tactile stimulus, we can effectively vary its perceived magnitude.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.133-144
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• 2003

Horizontal consolidation characteristics of Busan marine clay were investigated by computing coefficient of horizontal consolidation from Piezocone data and comparing their results with those of standard consolidation test. It is well known that current prediction models of $c_h$ for high plastic soils have large uncertainties, and show a great difference between the predicted and the measured values. However, the spherical models and expanding cavity theory of Torstensson(1977), and Burns & Mayne(1998) based on modified Cam-Clay model with critical limit state concepts have relative reliability in estimating $c_h$ and good applicability in highly plasticity soils. In this paper, a normalization technique was used to evaluate $c_h$ using the Burns and Mayne's method based on the dissipation test, and their normalized consolidation curves give 0.015 of time factor($T_{50}$) when 50% degree of consolidation is completed. Comparison study using Piezocone data obtained at other similar ground site shows 1.5 times less systematicality than that of standard consolidation test, which indicates considerable approximation with the measured values because standard consolidation test gives the difference of three to few times compared with the measured values. In addition, design chart for estimating $c_h$ based on the chart from Robertson et al.(1992) and using the other method of the direct prediction from the of dissipation test was newly proposed. It is judged that new proposed chart is very applicable to Korean marine soils, especially in very high plastic soils.

• Journal of the Korea Concrete Institute
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• v.15 no.4
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• pp.513-521
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• 2003

Existing tests results have shown that confining the concrete compression region with closed stirrups improves the ductility and load-carrying capacity of beams. However, only few researchers have attempted to utilize the beneficial effects of the presence of these stirrups in design. This paper presents the result of experimental studies on the load-deflection behavior and the strengthening effect of laterally confined structural high-strength concrete beam members in which confinement stirrups have been introduced into the compression regions. Fifteen tests were conducted on full-scale beam specimens having concrete compressive strength of 41 MPa and 61 MPa. Different spacing of stirrups(0.25∼1.0d) and amount of tension steel($0.55{\sim}0.7{\rho}_b$) as major variables were investigated. And also, this study present an appropriate shear equation for decision of ultimate failure modes of high-strength concrete beams according to stirrup spacing. The equation is based on interaction between shear strength and displacement ductility. Prediction of failure mode from presented method and comparison with test results are also presenteded

• Journal of the Korea Concrete Institute
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• v.19 no.2
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• pp.199-207
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• 2007

Strut-and-tie models for noncontact lap splices are presented and parameters affecting the effective lap length $(l_p)$ and the splice strength are discussed in this paper. The effective lap length along which bond stress is developed is shorter than the whole lap length. The effective lap length depends on the transverse reinforcement ratio $({\Phi})$ and the ratio of spacing to lap length $({\alpha})$. As the splice-bar spacing becomes wider, the effective lap length decreases and, therefore, the splice strength decreases. The influence of the ratio ${\alpha}$ on the effective lap length becomes more effective when the transverse reinforcement ratio is low. Because the slope of the strut developed between splice-bars becomes steeper as the ratio ${\Phi}$ becomes lower, the splice-bar spacing significantly affects the effective lap length. The proposed strut-and-tie models for noncontact lap splices are capable of considering material and geometric properties and, hence, providing the optimal design for detailing of reinforcements. The proposed strut-and-tie model can explain the experimental results including cracking patterns and the influence of transverse reinforcements on the splice strength reported in the literature. From the comparison with the test results of 25 specimens, the model can predict the splice strengths with 11.1% of coefficient of variation.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.10-19
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• 2012

In this paper, we propose an Adaptive Modulation and Coding (AMC) scheme using relay protocols generally known as Relay Node (RN). The AMC scheme is used for improving the throughput and a reliability of a communication system, because of the nature of different modulation and coding schemes. We analyze the performance of relay protocols with the AMC scheme and observed that relay protocols with the AMC scheme is capable of providing better average throughput at a lower Signal to Noise Ratio (SNR) level as compared to the conventional scheme with no AMC. We perform Monte Carlo simulations with Long Term Evolution-Advanced (LTE-A) parameters to prove the performance comparison of adaptive Modulation and Coding Scheme (MCS) relay protocols with the non-adaptive MCS relay protocols. The simulation results of the proposed system with adaptive MCS prove that among the Amplify-and-Forward (AF), Decode-and-Forward (DF) and DeModulate-and-Forward (DMF), the DMF protocol performs best at a lower SNR value and also provides better average throughput.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.91-105
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• 2016

Carbon Nanotube Field-Effect Transistors (CNTFETs) have been studied as candidates for post Si CMOS owing to the better electrostatic control and high mobility. To enhance the immunity against short - channel effects (SCEs), the novel channel and gate engineered architectures have been proposed to improve CNTFETs performance. This work presents a comprehensive study of the influence of channel and gate engineering on the CNTFET switching, high frequency and circuit level performance of carbon nanotube field-effect transistors (CNTFETs). At device level, the effects of channel and gate engineering on the switching and high frequency characteristics for CNTFET have been theoretically investigated by using a quantum kinetic model. This model is based on two-dimensional non-equilibrium Green's functions (NEGF) solved self - consistently with Poisson's equations. It is revealed that hetero - material - gate and lightly doped drain and source CNTFET (HMG - LDDS - CNTFET) structure can significantly reduce leakage current, enhance control ability of the gate on channel, improve the switching speed, and is more suitable for use in low power, high frequency circuits. At circuit level, using the HSPICE with look - up table(LUT) based Verilog - A models, the impact of the channel and gate engineering on basic digital circuits (inverter, static random access memory cell) have been investigated systematically. The performance parameters of circuits have been calculated and the optimum metal gate workfunction combinations of ${\Phi}_{M1}/{\Phi}_{M2}$ have been concluded in terms of power consumption, average delay, stability, energy consumption and power - delay product (PDP). In addition, we discuss and compare the CNTFET-based circuit designs of various logic gates, including ternary and binary logic. Simulation results indicate that LDDS - HMG - CNTFET circuits with ternary logic gate design have significantly better performance in comparison with other structures.

• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.31-46
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• 1997

In this paper, a parallel Optimal Best-First search Branch-and-Bound(B&B) algorithm(pobs) is designed and evaluated for MIN-based multiprocessor systems. The proposed algorithm decomposes a problem into G subproblems, where each subproblem is processed on a group of P processors. Each processor group uses tile sub-Global Best-First search technique to find a local solution. The local solutions are broadcasted through the network to compute the global solution. This broadcast provides not only the comparison of G local solutions but also the load balancing among the processor groups. A performance analysis is then conducted to estimate the speed-up of the proposed parallel B&B algorithm. The analytical model is developed based on the probabilistic properties of the B&B algorithm. It considers both the computation time and communication overheads to evaluate the realistic performance of the algorithm under the parallel processing environment. In order to validate the proposed evaluation model, the simulation of the parallel B&B algorithm on a MIN-based system is carried out at the same time. The results from both analysis and simulation match closely. It is also shown that the proposed Optimal Best-First search B&B algorithm performs better than other reported schemes with its various advantageous features such as: less subproblem evaluations, prefer load balancing, and limited scope of remote communication.