• Journal of Digital Convergence
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• v.15 no.4
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• pp.127-137
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• 2017

The role of smartphones is changing from a communication system for exchanging calls and information into a universal platform for cultural services. Also, satisfaction for mobile application services on smartphones is a very important factor in the smart business. In This paper, we analyze the effects of the outcome, service scape, costs, and especially the impact of whether costumers having to pay or free for the app on customer satisfaction. For this purpose, we analyzed survey data on service quality of mobile app service from Chinese mobile app service users. We also analyzed the moderating effects of paid and free mobile app services. As a result, it was confirmed that the quality, servicescape quality and cost of mobile app service that customers perceive have a positive effect on customer satisfaction. In addition, the effect of the cost of mobile app service perceived by the customer on customer satisfaction showed that free mobile app service was more significant than paid mobile app service. This paper can be used as an alternative to monetization for providing a mobile app service provider or a mobile app service provider who wants to switch mobile app service from free to paid service.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.13-18
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• 2016

In Long Term Evolution-Advanced (LTE-A), small cell enhancement(SCE) has been developed as a cost-effective way of supporting exponentially increasing demand of wireless data services and satisfying the user quality of service(QoS). However, there are many problems such as the transmission rate and transmission quality degradation due to the dense and irregular distribution of a large number of small cells. In this paper, we propose a clustering based interference management scheme in dense small cell network. We divide the small cells into different clusters according to the reference signal received power(RSRP) from user equipment(UE). Within a cluster, an almost blank subframe(ABS) is implemented to mitigate interference between the small cells. In addition, we apply the power control to reduce the interference between the clusters. Simulation results show that proposed scheme can improve Signal to Interference plus Noise Ratio(SINR), throughput, and spectral efficiency of small cell users. Eventually, proposed scheme can improve overall cell performance.

• Asian Spine Journal
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• v.12 no.6
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• pp.973-980
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• 2018

Study Design: Retrospective review. Purpose: To identify the trends in stimulator use, pair those trends with various grafting materials, and determine the influence of stimulators on the risk of revision surgery. Overview of Literature: A large number of studies has reported beneficial effects of electromagnetic energy in healing long bone fractures. However, there are few clinical studies regarding the use of electrical stimulators in spinal fusion. Methods: We used insurance billing codes to identify patients with lumbar disc degeneration who underwent anterior lumbar interbody fusion (ALIF). Comparisons between patients who did and did not receive electrical stimulators following surgery were performed using logistic regression analysis, chi-square test, and odds ratio (OR) analysis. Results: Approximately 19% of the patients (495/2,613) received external stimulators following ALIF surgery. There was a slight increase in stimulator use from 2008 to 2014 (multi-level $R^2=0.08$, single-level $R^2=0.05$). Patients who underwent multi-level procedures were more likely to receive stimulators than patients who underwent single-level procedures (p<0.05; OR, 3.72; 95% confidence interval, 3.02-4.57). Grafting options associated with most frequent stimulator use were bone marrow aspirates (BMA) plus autograft or allograft for single-level and allograft alone for multi-level procedures. In both cohorts, patients treated with bone morphogenetic proteins were least likely to receive electrical stimulators (p<0.05). Patients who received stimulation generally had higher reimbursements. Concurrent posterior lumbar fusion (PLF) (ALIF+PLF) increased the likelihood of receiving stimulators (p<0.05). Patients who received electrical stimulators had similar revision rates as those who did not receive stimulation (p>0.05), except those in the multilevel ALIF+PLF cohort, wherein the patients who underwent stimulation had higher rates of revision surgery. Conclusions: Concurrent PLF or multi-level procedures increased patients' likelihood of receiving stimulators, however, the presence of comorbidities did not. Patients who received BMA plus autograft or allograft were more likely to receive stimulation. Patients with and without bone stimulators had similar rates of revision surgery.

• Journal of Korean Society for Quality Management
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• v.11 no.1
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• pp.10-17
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• 1983

This paper studies item-life test plans with the specified item mean life $T_1$ (MTBF) - Producer's risk ${\alpha}$ and item mean life $T_2$ (MTBF, $T_2$ < $T_1$) - Consumer's risk ${\beta}$ when the probability of item survival follows the Weibull distribution (known shape parameter) as a expansion of [1]. And Operating Characteristic Curves and Average Life-testing Times of item-life test plans are computed for this paper and [1]. Cost analysis procedures are same as [1]. These results are computed by using computer program written in Level II Basic for Apple II Plus Micro-computer. Both this paper and [6] reduce the life-testing time for Weibull distribution in comparision with Exponential distribution, but results of [6] were computed for different criterions from this paper.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.5
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• pp.417-421
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• 2005

This study was to analyze the changes of levels of alkaline phosphatase before and after enucleation of jaw cysts combined with bone grafting, and to evaluate biochemically the effectiveness of the early detection of bone healing and infection as a prognostic marker. Eighteen patients (13 males, 5 females) with cystic lesions of the jaws were divided into two groups. The bone graft group underwent enucleation and bone graft. The control group underwent only enucleation. Both groups were measured levels of ALP before surgery, and plus-minus 4 weeks postoperatively. The more discriminating results were obtained in the bone graft group. The results were as follows : 1. Levels of ALP after enucleation of jaw cysts were decreased in all patients with and without bone graft. 2. The bone graft group showed more marked decrease in variation of levels of ALP than the control group.(p=0.008) This should be considered as a result of increased osteoblastic activity and new bone formation. 3. Such variation could be used as a prognostic marker for bone healing after cyst operation. In the cost/benefit ratio, measurement of ALP activity could be useful as a convenient procedure in routine clinical practice.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.1
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• pp.67-75
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• 2002

This paper presents a PLD design of Gray Mode Graphic STN LCD drive circuit using PC interface. The proposed LCD drive circuit doesn\`t use microprocessor for the convenience of users. Thus, the LCD drive circuit can transfer efficiently image data created under PC to LCD. The LCD drive circuit which is modelled in schematic capture, AHDL and VHDL is simulated in functionally through the use of ALTERA MAX+PLUS II. Also, timing simulation is performed by ALTERA EPM7192SQC160-15 PLD implementation. The PC interface part have been programmed in MS-Visual C++ 6.0. The validity and efficiency of the proposed LCD drive circuit have been verified by test board. After comparing this LCD drive circuit to specify it was verified that the developed LCD drive circuit showed good performances, such as convenience of users, low cost.

• Smart Structures and Systems
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• v.3 no.2
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• pp.189-200
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• 2007

As a functional material, shape memory alloy (SMA) has attracted much attention and research effort to explore its unique properties and its applications in the past few decades. Some of its properties, in particular the electrical resistance (ER) based self-sensing property of SMA, have not been fully studied. Electrical resistance of an SMA wire varies during its phase transformation. This variation is an inherent property of the SMA wire, although it is highly nonlinear with hysteresis. The relationship between the displacement and the electrical resistance of an SMA wire is deterministic and repeatable to some degree, therefore enabling the self-sensing ability of the SMA. The potential of this self-sensing ability has not received sufficient exploration so far, and even the previous studies in literature lack generality. This paper concerns the utilization of the self-sensing property of a spring-biased Nickel-Titanium (Nitinol) SMA actuator for two applications: ER feedback position control of an SMA actuator without a position sensor, and estimation of the opening of a SMA actuated valve. The use of the self-sensing property eliminates the need for a position sensor, therefore reducing the cost and size of an SMA actuator assembly. Two experimental apparatuses are fabricated to facilitate the two proposed applications, respectively. Based on open-loop testing results, the curve fitting technique is used to represent the nonlinear relationships between the displacement and the electrical resistance of the two SMA wire actuators. Using the mathematical models of the two SMA actuators, respectively, a proportional plus derivative controller is designed for control of the SMA wire actuator using only electrical resistance feedback. Consequently, the opening of the SMA actuated valve can be estimated without using an extra sensor.

• International Journal of Reliability and Applications
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• v.7 no.1
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• pp.27-39
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• 2006

Many real world cases in material failure analysis do not follow perfectly the normal distribution. Forcing of the normality assumption may lead to inaccurate predictions and poor product quality. We examine the failure process of the internal bond (IB or tensile strength) of medium density fiberboard (MDF). We propose a forced censoring technique that closer fits the lower tails of strength distributions and better estimates extremely smaller percentiles, which may be valuable to continuous quality improvement initiatives. Further analyses are performed to build an accelerated common-shaped Weibull model for different product types using the $JMP^{(R)}$ Survival and Reliability platform. In this paper, a forced censoring technique is implemented for the first time as a software module, using $JMP^{(R)}$ Scripting Language (JSL) to expedite data processing, which is crucial for real-time manufacturing settings. Also, we use JSL to automate the task of fitting an accelerated Weibull model and testing model homogeneity in the shape parameter. Finally, a package script is written to readily provide field engineers customized reporting for model visualization, parameter estimation, and percentile forecasting. Our approach may be more accurate for product conformance evaluation, plus help reduce the cost of destructive testing and data management due to reduced frequency of testing. It may also be valuable for preventing field failure and improved product safety even when destructive testing is not reduced by yielding higher precision intervals at the same confidence level.

• The Korean Journal of Emergency Medical Services
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• v.6 no.1
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• pp.27-37
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• 2002

The health and medical service attracts more public attention as the economy of Korea is rapidly growing up and the standard of living is elevated. Especially, the interest and demand on the prehospital emergency medical service that consists of the important part of primary medical service that is directly related to the life of patients are gradually increased. However, as compared with other advanced countries such as America in this area, Korea actually fell behind in the utilization of IT (Information Technology) to maximize the efficiency of emergency service system as well as has a problem in the general service system. This study suggested the necessity to introduce EMD (Emergency Medical Dispatch) system that takes a great role as the core part in the prehospital emergency medical service that is not systemized in Korea yet. In addition, this study proposed the implementation model of EMD ASP system using ASP (Application Service Provider) in EMD system to flexibly deal with the change of IT and efficient implementation and integration of information system as well as to significantly reduce cost through wire/wireless high speed Internet network that is politically promoted in Korea on the basis of EMD. The system analysis and design was executed by HIPO (Hierarchy Plus Input Process Output) analysis that was the conceptual design technology for EMD information system modeling based on ASP and DFD (Data Flow Diagram). This study proposed DB table configuration and data schema to implement the application of web browser interface in EMD system through ERD(ER-Diagram) of EMD ASP system. Finally, this study described how to implement and utilize EMD information system. This study aims to facilitate the qualitative development of emergency medical service in the future as suggesting the concrete models for the implementation of high value-added prehospital emergency medical information system as applying ASP concept to EMD system of prehospital emergency medical service area.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1768-1789
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• 2015

The maximal signal-to-interference-plus-noise ratio (Max-SINR) algorithm for interference alignment (IA) has received considerable attention for its high sum rate achievement in the multiple-input multiple-output (MIMO) interference channel. However, its complexity may increase dramatically when the number of users approaches the IA feasibility bound, and the number of iterations and computational time may become unacceptable. In this paper, we study the properties of the Max-SINR algorithm thoroughly by presenting theoretical insight into the algorithm and by providing the potential of reducing the overall computational cost. Furthermore, a novel IA algorithm based on the principle direction search is proposed, which can converge more rapidly than the conventional Max-SINR method. In the proposed algorithm, it searches along the principle direction, which is found to approximately point to the convergence values, and can approach the convergence solutions rapidly. In addition, the closed-form solution of the optimal step size can be formulated in the sense of minimal interference leakage. Simulation results demonstrate that the proposed algorithm outperforms the conventional minimal interference leakage and Max-SINR algorithms in terms of the convergence rate while guaranteeing the high throughput of IA networks.