• Journal of Advanced Marine Engineering and Technology
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• v.39 no.2
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• pp.159-165
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• 2015

Motion control schemes are generally classified into three categories (point stabilization, trajectory tracking, and path following). This paper deals with the problem which is associated with the initial deployment of a group of Unmanned Surface Vehicle (USVs) and corresponding point stabilization. To keep the formation of a group of USVs, it is necessary to set the relationship between each vehicle. A forcing functions such as potential fields are designed to keep the formation and a graph Laplacian is used to represent the connectivity between vehicle. In case of fixed topology of the graph representing the communication between the vehicles, the graph Laplacian is assumed constant. However the graph topologies are allowed to change as the vehicles move, and the system dynamics become discontinuous in nature because the graph Laplacian changes as time passes. To check the stability in the stage of deployment, the system is modeled with Kronecker algebra notation. Filippov's calculus of differential equations with discontinuous right hand sides is then used to formally characterize the behavior of USVs. The stability of the system is analyzed with Lyapunov's stability theory and LaSalle's invariance principle, and the validity is shown by checking the variation of state norm.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.1911-1915
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• 2012

Aim: New technologies for the early detection of pancreatic cancer (PC) are urgently needed. The aim of the present study was to screen for the potential protein biomarkers in serum using proteomic fingerprint technology. Methods: Magnetic beads combined with surface-enhanced laser desorption/ionization (SELDI) TOF MS were used to profile and compare the protein spectra of serum samples from 85 patients with pancreatic cancer, 50 patients with acute-on-chronic pancreatitis and 98 healthy blood donors. Proteomic patterns associated with pancreatic cancer were identified with Biomarker Patterns Software. Results: A total of 37 differential m/z peaks were identified that were related to PC (P < 0.01). A tree model of biomarkers was constructed with the software based on the three biomarkers (7762 Da, 8560 Da, 11654 Da), this showing excellent separation between pancreatic cancer and non-cancer., with a sensitivity of 93.3% and a specificity of 95.6%. Blind test data showed a sensitivity of 88% and a specificity of 91.4%. Conclusions: The results suggested that serum biomarkers for pancreatic cancer can be detected using SELDI-TOF-MS combined with magnetic beads. Application of combined biomarkers may provide a powerful and reliable diagnostic method for pancreatic cancer with a high sensitivity and specificity.

• Korean Medical Education Review
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• v.15 no.3
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• pp.125-135
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• 2013

Since the establishment of the national medical licensing examination board in 1992, the medical licensing examination system has changed enormously and this has had a number of impacts on examination services. All those reforms were aimed at improving the relevance and reliability of the test. Several attempts of the testing system have appeared in the new examination service, and which have also brought about the changes in the medical school curriculum such as introducing integrated courses instead of traditional subjects, using test scores as a reference to the post-graduation selection test. Some examples of changes in the examination system are as follows: 1) choosing three integrated test subjects and outlines of their reference content instead of 15 academic subjects, 2) adjusting the ratio of multiple choice question items to focus more on the problem solving level, 3) introduction of 'one-best answer' single set and 'extended matching type items, 4) item construction based on real clinical cases and real clinical materials. Recently, a clinical skill test system has been introduced to measure examinees' basic clinical skills competencies. Despite continuing efforts, the examination system still has many issues remaining to be solved. These problems include the differential weighting of test items, appropriate threshold for passing, and practicality of pre-testing to stabilize the passing rate and avoid the hazards of newness and undesirably difficult test items.

• Journal of Internet Computing and Services
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• v.9 no.4
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• pp.29-41
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• 2008

Currently, IETF MANEMO(Mobile Adhoc for NEMO) working group is working on standardization supporting internal routing in nested NEMO networks. Nested NEMO has a independent topology feature that Mobile IP and basic NEMO protocol did not caused. This is the reason that causes exceptional mobility pattern. Such mobility patterns also trigger each other reconfiguration requirements. This paper classified and analyzed probable new mobility patterns in nested NEMO network. In concludion, we derived configuration problem from the new mobility patterns and suggested differential reconfiguration requirements through analytical approach.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6B
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• pp.531-537
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• 2004

EPON which is the economical technology of FTTH is being actively researched as one of next generation of subscriber configurations. EPON based on Ethernet should provide subscriber with dynamic bandwidth allocation so as to support QoS. Allocation per service in grade should be satisfied resulting from the increment of the latest multimedia application arid consumption. In this paper, New Algorithm is proposed to serve differential service on MAC protocol. The delay characteristic of packet and stability are analyzed that is shown the QoS of EPON network.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.2
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• pp.31-40
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• 2004

Diff-Serv(DS) is a mechanism by which network service providers can offer differing levels of network service to different traffic, in so providing quality of service(QoS) to their customers. Because this mechanism has been deployed just for fixed hosts with the Token Bucket mechanism according to AggF(Aggregate Flow) instead of each flow, DS can not suggest effective usability of traffic resources. In this paper, we use WFQ mechanism for traffic conditioner and scheduling method monitoring the AggF and the results will be used to control the next flows coming in TC. So it will control traffic rate dynamically and suggest efficient usability of bandwidth.

• Journal of Communications and Networks
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• v.6 no.1
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• pp.9-18
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• 2004

Self-encoded multiple access (SEMA) is a unique realization of random spread spectrum. As the term implies, the spreading code is obtained from the random digital information source instead of the traditional pseudo noise (PN) code generators. The time-varying random codes can provide additional security in wireless communications. Multi-rate transmissions or multi-level grade of services are also easily implementable in SEMA. In this paper, we analyze the performance of SEMA in additive white Gaussian noise (AWGN) channels and Rayleigh fading channels. Differential encoding eliminates the BER effect of error propagations due to receiver detection errors. The performance of SEMA approaches the random spread spectrum discussed in literature at high signal to noise ratios. For performance improvement, we employ multiuser detection and Turbo coding. We consider a downlink synchronous system such as base station to mobile communication though the analysis can be extended to uplink communications.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.245-250
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• 2022

As location-based services using the Global Navigation Satellite System (GNSS) are diversified, concerns about the vulnerability of GNSS to radio disturbance and deception are also growing. Accordingly, countries that own and operate GNSS, such as the United States, Russia, and Europe, are also developing additional navigation systems that can compensate for GNSS' weaknesses. Among them, an R-Mode system that transmits navigation signals using an infrastructure that transmits differential GNSS (DGNSS) information using signals from the medium frequency band currently in operation is being developed in Europe and Korea. Since 2020, Korea has improved four DGNSS transmission stations, including Chungju, Eocheongdo, Palmido, and Socheongdo, to transmit R-Mode signals and test navigation performance in some parts of the West Sea. In this paper, we intend to establish a testbed for measuring the distance of R-Mode signals currently being transmitted and analyze the results. It is confirmed that the distance measurement performance varies depending on the antenna type, diurnal variation, and propagation path of the signal.

• Journal of Wellbeing Management and Applied Psychology
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• v.4 no.1
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• pp.1-10
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• 2021

Purpose: The study sought to uncover the effect of emotional labour strategies (surface acting and deep acting) on job satisfaction and emotional exhaustion. The study also purposed to analyse the moderating effect of organisational support (supervisory support and co-worker support) and the role of gender on emotional labour connotations. Research design, data and methodology: A conceptual framework was developed using extant literature which led to the examination of deep acting and surface acting, which are the two main strategies of emotional labour. The outcome variables were emotional exhaustion and job satisfaction. Data was collected from front line employees of banks and was analysed using SEM-AMOS version 21. Results: It was revealed, in this study, that surface acting is inversely related to job satisfaction and positively related to emotional exhaustion, whereas deep acting was positively related to job satisfaction and inversely related to emotional exhaustion. The roles of gender and organisational support were also confirmed. Conclusions: The study therefore concluded that deep acting is the most ideal strategy of emotional labour as it leads to job satisfaction and reduced emotional exhaustion. Surface acting is a harmful emotional labour strategy.

• Korean Journal of Social Welfare
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• v.36
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• pp.199-228
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• 1998

This study is designed to find out the determinants of dual-earner wives' needs for family-supportive services. For this purpose, a hypothetical model which explains the relationships among 6 stressors, role overload, stress and needs for 4 family-supportive services is developed. Using the data collected by purposive sampling from 234 professional women and 208 blue-collar women living in Chinju and Sacheon, the hypothetical model developed in this study was tested. In order to examine occupational class differences, a model for professionals and another model for blue-collars were developed separately and compared. For data analysis, a covariance structure analysis was used. The best-fitting model for professional women (df=141, GFI=0.928, CFI=0.965) and the model for blue collar women (df=141, GFI=0.902, CFI=0.912) were found. As a result of comparing two models, 9 common relationships were found:l)Greater dissatisfaction with child care service increases role overload; 2)Longer work hours increases role overload; 3) Higher level of role overload increases stress; 4)Higher level of stress increase needs for leaves; 5)Older child increases needs for flexible work pattern; 6)Younger child increases needs for finalcial assistance for child care fee; 7)needs for financial assistance for child care increases needs for on-site child care services; 8)needs for on-site child care services increases needs for leaves; 9)needs for leaves increases needs for flexible work pattern. With the exception of these 9 common relationships, the analyses revealed substantial differences between professional and blue-collar dual-earner wives. Based on the common and differential needs between 2 groups of wives, the effective ways to provide family-supportive services according to the needs of individual dual-earner wives who are in different familial, financial, and work conditions were suggested.