• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1481-1500
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• 2016

Device-to-Device (D2D) communication underlaying macro-small cell networks, as one of the promising technologies in the era of 5G, is able to improve spectral efficiency and increase system capacity. In this paper, we model the cross- and co-tier D2D communications in two-tier macro-small cell networks. To avoid the complicated interference for cross-tier D2D, we propose a mode selection scheme with a dedicated resource sharing strategy. For co-tier D2D, we formulate a joint optimization problem of power control and resource reuse with the aim of maximizing the overall outage capacity. To solve this non-convex optimization problem, we devise a heuristic algorithm to obtain a suboptimal solution and reduce the computational complexity. System-level simulations demonstrate the effectiveness of the proposed method, which can provide enhanced system performance and guarantee the quality-of-service (QoS) of all devices in two-tier macro-small cell networks. In addition, our study reveals the high potential of introducing cross- and co-tier D2D in small cell networks: i) cross-tier D2D obtains better performance at low and medium small cell densities than co-tier D2D, and ii) co-tier D2D achieves a steady performance improvement with the increase of small cell density.

• Journal of Digital Convergence
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• v.11 no.3
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• pp.189-197
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• 2013

Weak competitive Small Business are getting attention for their ability to enhance the brand power and marketing co-brand. Under these circumstances, in this study examined the operational status of the domestic co-branded. Also enable co-branding strategy was proposed. First, learn the various aspects of the concept of co-branding, and looked at the advantages and disadvantages of co-branding. Second, the type of co-branded partner combined, joint venture between companies Union type, a leading company driven and private companies and state agencies co-branded. Looked at the type of advantages and disadvantages of each. Thirdly, we presented the current status of the important co-branded domestic. Fourth, we examined the status of the Small and Medium Business Administration supports a co-branded Examined in detail by year look at the status of support for this type of co-branded Industry Distribution and co-branded interrupted. Finally, the short-term aspects and long-term perspective on the domestic co-brand activation strategy based on these materials are presented. The results of this study is expected to be the foundation of domestic co-branded business in the future to explore the ways to improve the system of government support will help to raise.

• Nuclear Engineering and Technology
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• v.50 no.1
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• pp.116-125
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• 2018

Modified 9Cr-1Mo ferritic steel is a preferred material for steam generators in nuclear power plants for their creep strength and good corrosion resistance. Austenitic stainless steels, such as type 316LN, are used in the high temperature segments such as reactor pressure vessels and primary piping systems. So, the dissimilar joints between these materials are inevitable. In this investigation, dissimilar joints were fabricated by the Shielded Metal Arc Welding (SMAW) process with Inconel 82/182 filler metals. The notch tensile properties and Charpy V-notch impact toughness properties of various regions of dissimilar metal weld joints (DMWJs) were evaluated as per the standards. The microhardness distribution across the DMWJs was recorded. Microstructural features of different regions were characterized by optical and scanning electron microscopy. Inhomogeneous notch tensile properties were observed across the DMWJs. Impact toughness values of various regions of the DMWJs were slightly higher than the prescribed value. Formation of a carbon-enriched hard zone at the interface between the ferritic steel and the buttering material enhanced the notch tensile properties of the heat-affected-zone (HAZ) of P91. The complex microstructure developed at the interfaces of the DMWJs was the reason for inhomogeneous mechanical properties.

• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.25-35
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• 2006

The purpose of this study was to investigate the shock attenuation mechanisms while varying the loads in a backpack during drop landing. Ten subjects (age: $22.8{\pm}3.6$, height: $173.5{\pm}4.3$, weight: $70.4{\pm}5.2$) performed drop landing under five varying loads (0, 5kg. 10kg. 20kg. 30kg). By employing two cameras (Sony VX2100) the following kinematic variables (phase time, joint rotational angle and velocity of ankle, knee and hip) were calculated by applying 2D motion analysis. Additional data, i.e. max vertical ground force (VGRF) and acceleration, was acquired by using two AMTI Force plates and a Noraxon Inline Accelerometer Sensor. Through analysing the power spectrum density (PSD), drop landing patterns were classified into four groups and each group was discovered to have a different shock attenuation mechanism. The first pattern that appeared at landing was that the right leg absorbed most of the shock attenuation. The second pattern to appear was that subject quickly transferred the load from the right leg to the left leg as quickly as possible. Thus, this illustrated that two shock attenuation mechanisms occurred during drop landing under varying load conditions.

• Physical Therapy Rehabilitation Science
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• v.4 no.1
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• pp.22-27
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• 2015

Objective: Jump training helps increase the muscle power by improving the muscle strength and reaction time of the muscle in operation. The purpose of this study was to identify the effects of strengthening, stretching exercise and meditation on electromyographic (EMG) onset timing of rectus femoris and gastrocnemius muscle during vertical jump performance. Design: Cross-sectional study. Methods: Ten healthy adults (5 male and 5 female) who were familiar with the vertical jumping task and had no lower extremity injuries or any bone or joint disorders, were recruited for this study. Muscle onset timing was measured by surface EMG. After EMG onset timing were measured during performing three baseline vertical jump trials, strengthening and stretching exercises of the rectus femoris and gastrocnemius, and meditation were performed in random order. EMG onset timing was measured during vertical jump after intervention, respectively. EMG value was averaged for the three trials and analyzed using one-way repeated ANOVA. Results: During vertical jump, EMG onset timing of gastrocnemius was a significant difference after intervention (p<0.05), and then there was significantly faster in strengthening exercise than meditation (p<0.05). Conclusions: These results indicate the potential positive effect of performing strengthening exercise of the gastrocnemius before a jumping event. Future research is required to identify the effects of intervention over a long period.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.53-59
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• 2009

In multi-user MIMO systems, a base station transmits multiple data to multi-user simultaneously in order to improve performance and bandwidth efficiency. When the base station transmits multiple data to multi-user simultaneously, multi-user interference occurs severely. In this paper, we define a post-processing leakage as the total power leaked from desired user to all other users after combining at the output of each user. Using concept of the post-processing leakage, we also define a performance metric, the so called signal-to-post-processing-leakage-plus-noise ratio (SPPLNR). Assuming that the receiver is the minimum mean square error (MMSE) receiver, we propose an iterative SPPLNR-based beamforming that determines beamforming vectors and combining vectors by using an iterative method. The proposed scheme does not impose a condition on the relation between the number of transmit antennas for the base station and the number of receive antennas for users. Simulation results show that the proposed scheme outperforms a beamforming scheme perfectly eliminating the multi-user interference when channel estimation error exists.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.2
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• pp.67-75
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• 2020

Objectives SJ004 is a natural herbal medicine that contains Acyranthes japonica Nakai and Eucommia ulmoides Oliver traditionally used for joint and spinal diseases. This study aimed to establish an efficient method of extracting SJ004 to standardize using the yield, high-performance liquid chromatography (HPLC), and antioxidant assay. Methods SJ004 was extracted with distilled water, 70% and 100% of ethyl alcohol (EtOH). The method validation of 20-hydroxyecdysone and pinoresinol diglucoside was determined by HPLC-photo diode array and the content of SJ004 was calculated. The antioxidant activity of each extract was compared and measured using total flavonoids, total phenolic compounds, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and ferric reducing antioxidant power according to the standard protocol. Results The yield was highest in pure water extract and lowest in 100% EtOH. But, the content of marker compounds indicating 20-hydroxyecdysone and pinoresinol diglucoside was highest in 100% EtOH extract. In the physiological activity measurement using antioxidant activity, 100% ethanol extract was highest. The limit of detection indicating 20-hydroxyecdysone and pinoresinol diglucoside were analyzed 0.33 ㎍/mL, 0.1616 ㎍/mL, and the limit of quantification were analyzed 1.01 ㎍/mL and 0.49 ㎍/mL respectively. Conclusions The experimental results showed that the extraction conditions have a significant effect on content of marker compounds and antioxidant activity. As a result of method validation, SJ004 was standardized by 20-hydroxyecdysone and pinoresinol diglucoside.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.124-131
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• 2008

Recently underground electrical power distribution is increased because people attach importance to aesthetics of the downtown areas. Lew-voltage handhole of underground distribution line for joint and branch point is mainly installed at the sidewalk. So, pedestrian can get a electric shock if fault is occurred in the low-voltage handhole. Furthermore the street was flooded by recently an unusual change in the weather. Fault is occurred in the low-voltage handhole that may create a shock hazard for the human body because a person's body resistance lower due to effect of water. This paper analyses causes of electric shock accidents and check results at the low-voltage handhole. At a result of analysis, the causes of electric shock accidents in domestic and foreign low-voltage handhole are same but environmental conditions of low-voltage handhole are different In the future, the analytical data can be applied to prevent the electric shock at the low-voltage handhole, and can be used to basic data for the improving installment of low-voltage handhole.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.37-43
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• 2010

When lightning surges with wide frequency spectrum and power converting devices are considered, it is desirable to evaluate grounding system performance by grounding impedances. This paper presents the measured results for frequency-dependent grounding impedance for the vertical grounding electrode and counterpoise on a scale of full size. Grounding impedances of vertical grounding electrodes and counterpoises give capacitive or inductive behaviors according to the length of grounding electrodes and soil resistivity. It is inefficient to extend the length of the grounding electrode in order to decrease the ground resistance, and when designing the grounding system, the consideration of the grounding impedance should be desirable. In order to reduce the grounding impedance of counterpoise, the grounding conductors are jointed at the center of counterpoises. It is effective to reduce the grounding impedance by connecting ground rods to counterpoises in parallel.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.1008-1020
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• 2018

In this paper, the dynamic compliance and its compensation control of the force control system on the highly integrated valve-controlled cylinder (HIVC), the joint driver of the hydraulic drive legged robot, is researched. During the robot motion process, the outer loop dynamic compliance control is applied on the base of hydraulic control inner loop and most inner loop control are the force or torque closed loop control. While the dynamic compliance control effectiveness of outer loop can be affected by the inner loop self-dynamic-compliance. Based on this problem, the dynamic compliance series composition theory of HIVC force control system as well as the analysis of its self-dynamic-compliance is proposed. And then the paper comes up with the compliance-enhanced control, which is a compound compensation control method of dynamic compliance with multiple series branches. Finally, the experiment results indicate that the control method mentioned above can enhance the dynamic compliance of HIVC force control system observably. This provides the compensation control method of inner loop dynamic compliance for the outer loop compliance control requiring the high accuracy and high robustness for the robot.