• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.7 s.98
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• pp.681-689
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• 2005

This paper presents an ultra wide band(UWB) mixer using anti-parallel diode pair(APDP) with simulation and measurement results. The proposed mixer adopts the even-harmonic direct conversion mixing, which consists of a couple of filter, in-phase wilkinson power divider, wideband $45^{\circ}$ power divider, and APDP. The m mixer is operating over 3.1 to 4.8 GHz and producing quadrature(I/Q) outputs with a conversion loss of 18 dB and input third order intercept point($IIP_3$) of 15 dBm. I/Q outputs also have difference of about 0.5 dB and phase difference of ${\times}3^{\circ}$ and $P_{1dB}$ of 2 dBm.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.1
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• pp.63-70
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• 2007

This study investigated the current management staus of chemical substance information on Material Safety Data Sheets(MSDS) and Chemical Information Cards(CIC) provided by Korea Occupational Safety & Health Agency(KOSHA) and also researched the kind and the characteristics of chemical substance information provided in other organizations. MSDS DB in Korean provided on KOSHANET(which is Kosha website) is 50,802 in total, among whom are single chemical substances with 31,870 kinds(18,932%) and are mixed chemical substances with 31,870 kinds(62.7%). The number of visiting MSDS DB on KOSHANET for the search of chemicals was 2,049,806. The number has increased each year. The CIC provided for workplaces is all 542 kinds : 14 harmful substances subject to permission, 168 harmful substances subject to management, 360 KOEL(Korean Occupational Exposure Limits) establishment substances. MSDS internationally provided by organizations producing MSDS DB was written with 16 sections, which is suitable for the writing basis of American Standards Institute(ANSI) and International Organization for Standardization(ISO) and provided chemical substance information on more than 100,000 kinds in most organizations.

• Journal of Society of Preventive Korean Medicine
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• v.19 no.2
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• pp.1-12
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• 2015

Objective : This study was a covariance structural analysis to identify korean medicine health promotion behavior by the general characteristics of the subjects and build a predictive model and theoretical framework based on Pender's health promotion model(1996) and related literature reviews. Method : A hypothetical model was consisted of 8 theoretical variables and 27 measured variables. Related variables included Individual Characteristics and Experience, Behavior-specific cognitions and affect and Behavioral outcome. The data was collected from 802 middle and old-aged people living in Seoul and Gyeong gi province through structured questionnaires by face to face interviews between February and March, 2014. SAS ver. 9.1 and AMOS 18.0 programs were used for the data analysis. Results : Difference in the verification of Korean medicine health promotion behavior by the general characteristics, Older people who are male, with higher economic status, no chronic disease or with diabetes, no smoking, no drinking, with more exercise showed significantly higher scores, but education level has no difference. 15 paths were statistically significant among 16 paths on the direct effect, 6 paths were statistically significant among 9 paths on the indirect effect in the hypothetical model. The greatest impact variable on Korean medicine health promotion behavior was perceived self-esteem. Also, the findings showed that the higher perceived social support, perceived health status, previous Korean medicine health promotion behavior, community environment, perceived benefit and the lower perceived barrier had a significant effect on Korean medicine health promotion behavior. Conclusion : This research model has an empirical validity as the variables of this study verified their effects and significances. Therefore, the understanding of Korean medicine health promotion behavior can be increased and the utilization will be higher when seeking a comprehensive health promotion plan. Also, a strategy can be utilized the strategy for Korean medicine health promotion behavior.

• The Journal of the Korea Contents Association
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• v.7 no.10
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• pp.10-18
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• 2007

Today, third-generation(3G) of mobile communication service executing the video and TV. And low cost, high speed data rate will emerge communication of the fourth generation(4G) in future. So, in this paper we studied occupied frequency bandwidth of common technique criteria among the technique criteria for the 4G mobile communication of FDD-based on Up/Down-link. The mobile communication traffic is predicted Up/Down-link of non-symmetric in future. So we proposed the PHY layer parameters of occupied frequency bandwidth of Up/Down-link with both 1:3 and 1:6. We also verified this through the simulation. We proposed the occupied frequency bandwidth for the 4G mobile communication in this paper.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.1965-1967
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• 2013

Background: To obtain the maximum additional information about the prognosis of gastric cancer, we compared CA-50 with other previously defined markers. Materials and Methods: This hospital based study was carried out in the Department of Biochemistry of Nepalese Army Institute of Health Sciences between $1^{st}$ July 2012 and $31^{st}$ December 2012. The variables collected were age, gender, AFP, CEA, CA19-9, and CA50, assayed with ELISA reader for all cases. The cut off values for serum AFP, CEA, CA19-9, and CA-50 were 10 ${\mu}g/l$, 10 ${\mu}g/l$, 37 U/ml, and 20 U/ml, respectively according to the manufacturer's instructions. Approval for the study was obtained from the institutional research ethical committee. Results: Of the 40 examined patients, 13 patients had tumors located in the upper third of the stomach, 6 patients had tumors in the middle third, 16 patients had tumors in the lower third, and 5 patients had tumors occupying two-thirds of the stomach or more. The distribution of lymph node staging of the patients was as follows: 7 patients belonged to N0, 9 patients to N1 stage, 10 patients to N2 stage, and 14 patients to N3 stage. The statistical method of Cox proportional hazards using multivariate analysis also illustrated that tumor markers including CEA (2.802), CA19-9 (2.690), CA50 (2.101), were independent prognostic factors, as tumor size (1.603), and lymph node stage (1.614). Conclusions: The tumour markers now available, like CEA, CA 19-9 and CA 50, chiefly perceive advanced gastric cancer. The preoperative rise in those tumour marker level have a prognostic significance and may be clinically helpful in choosing patients for adjuvant management.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.91-99
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• 2009

Mobile WiMAX is an emerging technology that can provide ubiquitous Internet access. To provide seamless service in mobile WiMAX environment, delay or disruption in dealing with mobility must be minimized. However offering seamless services on IEEE 802.16e networks is very hard due to long handover latency both in layer 2 and 3. In this paper, we propose a fast cross-layer handover scheme based on prediction algorithm. With the help of the prediction, layer-3 handover activities are able to occur prior to layer-2 handover, and therefore, total handover latency can be reduced. The experiments conducted with system parameters and propagation model defined by WiMAX Forum demonstrate that the proposed method predicts the future signal level accurately and reduces the total handover latency.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.57-60
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• 2003

IEEE 802.16 Wireless MAN standard specifies the air interface of fixed point-to-multipoint broadband wireless access systems providing multiple service. Among the service classes supported by the wireless MAN, the BE class is ranked on the lowest position in priority and is usually deployed by multicast and broadcast polling MAC scheme. In provisioning such BE service, the delay performance is influenced by a number of components including restrictions on resource request per SS, the number of request opportunities in upward frame, scheduling requests at BS, and contention resolution method. As candidate components of MAC function for BE service, we propose single and multiple request schemes (for controling the number of requests per SS), exhaustive and limited request schemes (for regulating the amount of grant per request) and FCFS, H-SMF, pure SMF, SS-wise Round Robin, and pure Round Robin (for scheduling requests at BS). Then, we construct MAC schemes by combining the above components and evaluate the delay performance exhibited by each MAC scheme using a simulation method. From numerical results, we investigate the effect of MAC components on average delay and delay variation and observe the dissonance on collision reduction in a resource - limited environment.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.562-570
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• 2011

In this paper, a distributed mobile relay power control (DMRPC) scheme for maximizing individual cell throughput is proposed for mobile relay aided multi-cell orthogonal frequency division multiplexing (OFDM)-time division duplex (TDD) system. In the system with DMRPC, the power levels of relay's are controlled by individual cell without cell cooperation and signalling overhead. It is demonstrated by numerical simulation that DMRPC provides the better cell throughput performance than either the full power relay aided system or conventional system without relay does. Moreover, it is also shown that relay aided systems with DMRPC, and the conventional system have almost identical cell edge throughput, while full power relay aided systems show worse performance in cell edge throughput.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.799-808
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• 2005

This paper proposes low latency handover procedure for seamless connectivity and QoS support between wired (e.g. Ethernet) and wireless (e.g. WLAN, WiBro(802.16-compatible), CDMA) networks by the mobile-assisted and server-initiated handover strategy. It is assumed that the server decides the best target network considering network status and user preferences. In this algorithm a mobile terminal associates with the wireless link decided at the server In advance and receives CoA as well. When handover occurs without the prediction in wired networks, the server performs fast binding update using physical handover trigger through the MIH(media independent handover) function. As a result, a mobile terminal does not need to perform L2 and L3 handover during handover so that this procedure decreases handover latency and loss.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.441-450
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• 2006

WiBro(Portable Internet Service) is service being capable to provide a high data rate wireless internet access with Personal Subscriber Station under the stationary or mobile environment, anytime and any where. It will fill the gap between very high data rate wireless local area networks and very high mobility cellular systems. The security is an important point of WiBro providing high data and mobile wireless services. This paper proposes user authentication mechanism of WiBro wireless networks applied EAP-AKA authentication protocol. As a result of Wireless authentication based on EAP-AKA, this mechanism is capable to be used in WiBro-WLAN-3GPP interworking scenario as well as the WiBro authentication mechanism.