• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3B
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• pp.112-122
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• 2008

Basing on Piconet, The Bluetooth System forms network and transmits data. There is one Master and maximum 7 Slave bluetooth devices in one piconet. A job scheduler performed by Master bluetooth device, gives the chance of data transmission to Slave bluetooth devices, which connected to Master, using polling method in piconet. The maximum data rate is 723.2 kb/s when it uses ACL link with DH5 packet type in a piconet which is constructed by two bluetooth devices. However, if there are one master and two slave devices in a piconet, then the maximum data rate is reduced to a half(361.6kb/s), because a master device has to support same data rate for all connected devices. And, there is the defect in scatternet when data transmission rate becomes low(Maximum rate: 302.2kb/s). This paper proposals the new ad-hoc network topology called "DoublePico"for overcome the low data transmission in scatternet which is constructed by piconets. The method of doublepico that represented in this paper makes high data transfer rate(Maximum rate: 457.57kb/s) in bluetooth ad-hoc networks.

• Korean Journal of School Psychology
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• v.17 no.2
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• pp.181-198
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• 2020

This study examined how the rejection sensitivity model might be applied to the link between rejection sensitivity and dating relationship satisfaction by means of investigating the mediating effect of cognitive emotion regulation strategy and conflict resolution strategy. A total of 668 college students in Seoul (232 males, 436 females, mean age of 21.59 years [SD=2.08]) participated in this study. The results illustrated that the adaptive emotion regulation strategy, among cognitive emotion regulation strategies, and the integration and compromise strategies, among conflict resolution strategies, had the double mediation effect on the association between rejection sensitivity and dating relationship satisfaction. In other words, a direct negative correlation between rejection sensitivity and dating relationship satisfation resulted in high rejection sensitivity, which was expected to generate low satisfaction in dating relationships. However, it was confirmed that the use of these two strategies-the cognitive emotion regulation and the conflict resolution strategy-could bring positive effects in terms of the dating relationship satisfaction; the former helped couples to see situations more broadly and increase positive perceptions, while the latter solve their problems each other. Based on these findings, we discuss their implications for counseling practice and therapeutic interventions

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.8
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• pp.1250-1258
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• 1997

This paper reports on the development of a new foot for a quadrupedal jointed-leg type walking robot. The foot has 2 toes, one at the front and the other at the rear side, for stable landing on uneven ground by point contact. The toes can move up and down independantly, guided by double-wishbone shaped parallel links which enable the lower leg to rotate with respect to a remote center on the ground surface. The motion of each toe is damped by a hydropneumatic shock absorber integrated in the foot in order to absorb the dynamic landing shock. Furthermore, the new foot can reduce the maximum hip joint drive torque by shortening the moment arm length between the hip joint and the landing force vector on the ground. Intensive experiments were carried out in this study by using a one-leg walking model to investigate the soft landing performance of the foot which could be hardly offered by conventional robot feet such as a flat plate with a gimbal type ankle joint. And it was confirmed that the hip joint torque of the leg walking on the flat surface could be reduced remarkably by using the new foot.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.629-635
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• 2009

The FSK duplex remote controlling wireless transmission units with a common local oscillator circuit for transmitter and receiver are designed and implemented in this paper. In the FSK full-duplex the channel frequency for Tx/Rx is allocated, a common switching oscillator circuit for Tx/Rx is designed in the FSK half-duplex scheme. Both of FSK units get functions of automatic channel detection for busy channels and channel configuration for an idle channel in order to reduce the RF channel interference and are designed as a remote controller with small-sized low power of 10mW and the 400MHz-colpitz type PLL configuration of 50kHz channel separation. The full-duplex Tx/Rx link frequency gets frequency difference of 42.8MHz, which is double of 21.4MHz IF frequency.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.993-1001
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• 2016

Type 2 diabetes mellitus patients are at increased risk of many forms of malignancies, especially of the pancreas, colon and hepatocellular cancer. Unfortunately, little is known of the possible interaction between antidiabetic drugs and anticancer agents. The present study investigates the influence of metformin (MET) and sitagliptin (SITA) on the in vitro anticancer activity of the microtubule depolymerization inhibitor agent epothilone A (EpoA). Hepatocellular liver carcinoma cell line (HepG2) viability and apoptosis were determined by the MTT test and by double staining with PO-PRO-1 and 7-aminoactinomycin D, respectively, after treatment with EpoA, metformin or sitagliptin. The levels of nuclear factor NF-${\kappa}B$ and p53 were evaluated in the presence and absence of inhibitors. While EpoA and MET inhibited HepG2 cell proliferation, SITA did not. EpoA and SITA induced higher p53 levels than MET. All tested drugs increased the level of NF-${\kappa}B$. Only MET enhanced the proapoptotic effect of EpoA. The EpoA+MET combination evoked the highest cytotoxic effect on HepG2 cells and led to apoptosis independent of p53, decreasing the level of NF-${\kappa}B$. These findings support the link between NF-${\kappa}B$ and p53 in the modulation of apoptotic effects in HepG2 cells treated by EpoA. Our studies indicate that the combination of EpoA and MET applied in subtoxic doses has a stronger cytotoxic effect on liver cancer cells than each of the compounds alone. The therapeutic advantages of the combination of EpoA with MET may be valuable in the treatment of patients with diabetes mellitus type 2 (T2DM) and liver cancer.

• Progress in Superconductivity and Cryogenics
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• v.18 no.1
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• pp.59-63
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• 2016

The superconducting NMR magnets have used cryogen such as liquid helium for their cooling. The conduction cooling method using cryocoolers, however, makes the cryogenic cooling system for NMR magnets more compact and user-friendly than the cryogen cooling method. This paper describes the thermal and structural analysis of a cryogenic conduction cooling system for a 400 MHz HTS NMR magnet, focusing on the magnet assembly. The highly thermo-conductive cooling plates between HTS double pancake coils are used to transfer the heat generated in coils, namely Joule heating at lap splice joints, to thermal link blocks and finally the cryocooler. The conduction cooling structure of the HTS magnet assembly preliminarily designed is verified by thermal and structural analysis. The orthotropic thermal properties of the HTS coil, thermal contact resistance and radiation heat load are considered in the thermal analysis. The thermal analysis confirms the uniform temperature distribution for the present thermal design of the NMR magnet within 0.2 K. The mechanical stress and the displacement by the electromagnetic force and the thermal contraction are checked to verify structural stability. The structural analysis indicates that the mechanical stress on each component of the magnet is less than its material yield strength and the displacement is acceptable in comparison with the magnet dimension.

• Journal of Family Resource Management and Policy Review
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• v.15 no.3
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• pp.131-151
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• 2011

This study attempted to estimate the level of perceived lack of time in Korean society, to link it to time management and to identify the possible association that accounts for time shortage. I employed the gender perspective in order to reveal the dynamics and complexity of the perception of a lack of time in the population. The sample for the study was drawn from the 1999 and 2009 Korean time diary data collected by the Korean National Statistical Office. From the original data, I selected a sample of second shift families(men and women who are presently working and raising children) living in metropolitan areas(including Seoul and six major urban areas in Korea). The dependent variable was time pressure measured by a single-item question on a four-point likert scale. The results of the study showed that working mothers perceived a greater time shortage as compared to working fathers. The time use pattern showed change during the periods, indicating that people worked fewer hours in paid labor and enjoyed more leisure hours and personal care hours. However, on average, people seemed to have experienced a greater time lack in 2009 as compared to 1999. The results from the ordered logistic regression model revealed that even though there were similarities in the impact of relevant factors, men's perception of a lack of time was more closely linked with their work role and social status, while for women, this perception was influenced by work and family duties. This indicates that Korean working mothers and fathers are facing a double jeopardy of time shortage in terms of combining their work and family roles. As a result, the level of time pressure by gender is converging toward a "never enough" phase. These findings generated policy implications and detailed suggestions.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.3
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• pp.867-872
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• 2012

Background: $FOXP3^+$ regulatory T cells (Tregs) inhibit effector T cell functions and are implicated in tumour progression. However, together with microvessel density (MVD) they remain controversial prognostic predictors for renal cell carcinoma (RCC), and potential associations have yet to be determined. The objective of this study was to determine the prognostic significance of Tregs and MVD and their potential relationship in RCCs. Design: Paraffin-embedded tissues from 62 RCC patients were analysed using immunohistochemistry to detect $FOXP3^+$ lymphocytes, and double immunohistochemistry to detect different microvessel types in the tumour interior, rim and normal kidney tissue, and their correlation with clinicopathological characteristics. Survival analysis was also performed. Results: The presence of $FOXP3^+$ cells in the tumour interior or the rim showed no correlation with death from RCC and other pathological characteristics. Negative correlations were noted between the immature MVD in the tumour interior or the rim and tumour size, tumour stage and overall survival; however, there was no correlation with the nuclear grade or pathological type. A positive correlation between $FOXP3^+$ Tregs and immature MVD (r=0.363, P=0.014) and mature MVD (r=0.383, P=0.009) was confirmed in the tumour interior. However, there was no correlation between $FOXP3^+$ Tregs and mature MVD (r=0.281, P=0.076) or immature MVD (r=0.064, P=0.692) in the tumour rim. Conclusions: In this study, a positive correlation between the presence of $FOXP3^+$ Tregs and immature and mature MVD in RCC was confirmed, which suggests a link between suppression of immunity, tumour angiogenesis and poor prognosis.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.625-631
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• 2010

In this paper, robustness performance of SNUR message is compared with those of existing ones, RTCM(Radio Technical Commission for Maritime Services) v2 MT(Message Type) 18/19 and MT 20/21 under a poor broadcast condition such as temporary data loss or disconnection We defined the temp oral data loss as 2 second delay and reconnection after disconnection as 7 second latency, and then evaluated its robustness for each latency case by double differentiating the observables. Our result shows that SNUR protocol method can reduce the latency error of the existing RTCM messages by 30~60%. Moreover, a rover using SNUR message, whose latency error is bounded within 1/4 L1 wave length, can figure out its own fixed position continuously in spite of 7 second disconnection, while the other using RTCM message, whose error is larger than half wave length, cannot keep its previous fixed solution.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.115.1-115.1
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• 2011

We analyzed the line profiles of the planetary nebula (PN) NGC 7009 secured with the Keck I HIES and BOES's spectral data. The 5 positions were taken over the nebular image, 4 points on the bright rim plus 1 point at the central position. The covered spectral wavelength range was $3250{\AA}-8725{\AA}$ in these observations. We decomposed the lines of HI, HeI, HeII, CII, NIII, [ClIII], [NII], [OII], [OIII], [SII], [SIII], [ClIII], and [ArIII] using the IRAF and StarLink/Dipso. After correcting the Earth's movement and the PN's radial velocities, -48.6 & -48.9 km/s, respectively, for the Keck & BOES, we produced the line profiles in a velocity scale. The zero velocity at each line profile clearly indicates which part of the components is approaching or receding, giving a general information of the kinematical structure. Almost all of the low-to-medium excitation lines, such as [NII], [SII], [O III], and [ArIII], secured at the central position and four positions along the major & minor axes, showed 3 components, double peak + a wide wing component, suggesting the fast outflow structures are present. The overall geometry is a prolate shell which also has a fainter outer shell in the halo zone, but there appears to be some peculiar sub-structures inside the main shell. The high excitation He I, HeII, NIII lines which might be formed close to the inner boundary of the shell show unusual features, completely different from the other lines. The HeII and these high excitation lines may be indicative of a relative recent fast outflow from the central star and the permitted lines such as NIII might be affected by the innermost structure. We discuss a possible presence of a jet-like fast outflow structure in an out-flow axis different from the main axis of the spheroid shell.