• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.1
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• pp.99-104
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• 2014

Nowadays, various researches fulfill in many communication engineering area for B4G (Beyond Forth Generation). Next LTE-A (Long Term Evolution Advanced), MU-MIMO (Multi-User Multi Input Multi Output) method raises to upgrade throughput performance. However, the method of user selection is not decided because of many types and discussions in MU-MIMO system. Many existing methods are powerful for enhancing performance but have various restrictions in practical implementation. Fairness problem is primary restriction in this area. Existing papers emphasis algorithm to increase sum-rate but we introduce an algorithm about dealing with fairness problem for real commercialization implementation. Therefore, this paper introduces new user selection method in MU-MIMO system. This method overcomes a fairness problem in SUS (Semiorthogonal User Selection) algorithm. We can use the method to get a similar sum-rate with SUS and a high fairness performance. And this paper uses a hybrid method with SC-SUS (Superposition Coding SUS) algorithm and SUS algorithm. We find a threshold value of optimal performance by experimental method. We show this performance by computer simulation with MATLAB and analysis that results. And we compare the results with another paper's that different way to solve fairness problem.

• Fashion & Textile Research Journal
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• v.23 no.5
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• pp.655-666
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• 2021

This study aims to classify wearable devices for infants and children according to their function, and to analyze the types and attachment methods of the devices by function, operating system, characteristics of materials, and types of batteries, and to identify the points for improvement. Forty-eight types of devices investigated through previous studies and keyword research online were analyzed. Wearable devices for infants and children were classified according to their functions into wearable monitors, wearable thermometers, GPS trackers, and smart watches. Devices had different shapes and attachment methods according to their functions, and were mainly clothes or accessory types. The accessory type devices were attached to the body using velcro, clips, bands, or adhesives. Wearable monitors and thermometers mainly used Bluetooth to transmit data wirelessly, and location trackers used various combinations of 4G(LTE), 5G networks, GPS, Wi-Fi, and Bluetooth. Smartwatches had different functions depending on whether smart phones were linked to them or not. Wearable monitors and thermometers mainly used by infants provided material information, but other devices did not. These devices used rechargeable, replaceable, non-rechargeable or non-replaceable batteries. Wearable devices need to be improved to reduce the discomfort experienced by infants and children due to the attachment position, malfunction, skin trouble caused by materials, short time of use of batteries, version conflict and complexity with the device when linking with a smart phone, and non-operation when using Bluetooth.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2507-2517
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• 2015

In this research, we aim to analyze the trend of Huawei's PCT patent applications. As a result of analyzing Huawei's PCT patents by dividing temporal spans into three periods - the early 2000s, the late 2000s, and the early 2010s -, the following characteristics have been observed. First, the number of PCT patent applications has conspicuously increased from the early 2000s to the late 2000s and this trend has continued during the early 2010s. Second, in terms of a core technological field, whereas Huawei focused on the development of technologies in the 'H04L: transmission of digital information' sector during the early/late 2000s, it changed this field to the 'H04W: wireless communication networks' sector during the early 2010s. Lastly, in the case of the patent maps, it was found that while general communications technologies, as expressed with such keywords as 'user' and 'network,' were actively developed during the early/late 2000s, mobile phone-related technologies grasped this leading position, as shown with the keywords including 'user equipment,' 'base station,' and 'MME,' during the early 2010s. It was also noticeable that Huawei filed LTE-related patent applications more actively than Apple and Samsung Electronics, which implies that it will presumably pioneer the global market more aggressively than its competitors in the future.

• Journal of The Korean Astronomical Society
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• v.24 no.1
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• pp.71-94
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• 1991

With the 14 m radio telescope at DRAO and the 4 m at Nagoya University, we have made detailed maps of $^{12}CO$ and $^{13}CO$ emissions from two Barnard objects B133 and B134 in the $J=1{\rightarrow}O$ rotational transition lines. Usual LTE analyses of the CO observations led us to determine the distribution of column densities over an entire area encompassing both globules. Total gas masses estimated from the column density map are $90\;M_{\odot}$ and $20\;M_{\odot}$ for B133 and B134, respectively. The radial velocity of B133 is red shifted with respect to B134 by $0.8\;km\;s^{-1}$, which is too lagre to bind the two clouds as a binary system. We have shown that the usual stability analysis based on the simplified version of virial theorem with the second time-derivative of the moment of inertia term $\ddot{I}$ being ignored could mislead us in determining whether a given cloud eventually collapses or not. The lull version of the scalar virial theorem with the $\ddot{I}$ term is shown to be useful in following up the time-dependent variations of the cloud size R and its streaming velocity $\dot{R}$ as functions of time. Results of our stability analysis suggest that B133 will eventually collapse in $(2{\sim}4){\times}10^6$ years.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.32-32
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• 2020

하나의 수계 또는 용수구역 내에서 작물생육기간 동안 지하수자원 수요량의 집중적인 증가로 인해 지역적 지하수 고갈이 발생하여 농작물 피해가 발생하고 있으며 과잉양수로 인한 지하수위 하강으로 사용자간 갈등도 빈번하다. 또한, 기후변화로 인해 극한기후인 가뭄의 잦은 발생은 이러한 현상을 가속화 한다. 지하수 산출성이 좋은 대수층의 공간적 분포는 복잡한 지질구조로 인해 균일하지 않으며 같은 대수층 내에서도 양수 위치에 따라 산출성은 다르게 나타난다. 이러한 지하수 수요와 공급 및 대수층 분포로 인한 지하수자원 불균형의 해소를 위해 지하수가 풍부한 지역에서 부족한 지역으로 지하수를 공급하는 방법을 적용할 수 있다. 이때 기술적용 지역의 지하수 사용 상황 및 공급 가능량을 정량적으로 평가하고 이를 기반으로 지하수 공급을 제어하는 것이 매우 중요하다. 지하수자원의 수요-공급 불균형이 발생할 때 즉각적으로 대응하기 위해서는 실시간으로 지하수 현황을 감시하고 이를 기반으로 공급 가능량을 산정할 필요가 있으며 이는 정보통신기술(Information and Communication Technology, ICT)에 기반한 관정연계관리체계(Well Network System, WNS)를 구성하는 기술 중 하나인 관정군집제어 기술로 구현될 수 있다. 수계 내에 설치된 기존의 양수정과 새롭게 추가된 관측정들을 4G LTE 네트워크를 통해 하나의 관정군으로 묶고 중앙 서버를 통한 자료 분석 및 양수 펌프 제어를 통해 대수층의 공급 능력과 사용자의 수요 현황에 따른 지하수자원의 체계적 분배를 구현하고자 하였다. 관정군집제어는 관정별 지하수위 및 양수정 양수량을 실시간으로 관측하고 이를 분석서버에 전송하여 해당 지하수계의 공급 가능량 및 인접관정 간섭 등을 분석하여 양수정의 펌프를 실시간으로 제어하고 양수된 지하수를 수요 지역으로 이송한다. 본 연구를 통해 관정군집제어 기술의 구현에 필요한 구성요소를 정의하고 이에 대한 구현 방법을 기술하여 WNS를 구성하는 하나의 요소기술 모델로 제시하고자 하였다.