• International Journal of Computer Science & Network Security
• /
• 제24권1호
• /
• pp.226-234
• /
• 2024

The frequent handover problem and playing ping-pong effects in 5G (5th Generation) ultra-dense networking cannot be effectively resolved by the conventional handover decision methods, which rely on the handover thresholds and measurement reports. For instance, millimetre-wave LANs, broadband remote association techniques, and 5G/6G organizations are instances of group of people yet to come frameworks that request greater security, lower idleness, and dependable principles and correspondence limit. One of the critical parts of 5G and 6G innovation is believed to be successful blockage the board. With further developed help quality, it empowers administrator to run many systems administration recreations on a solitary association. To guarantee load adjusting, forestall network cut disappointment, and give substitute cuts in case of blockage or cut frustration, a modern pursuing choices framework to deal with showing up network information is require. Our goal is to balance the strain on BSs while optimizing the value of the information that is transferred from satellites to BSs. Nevertheless, due to their irregular flight characteristic, some satellites frequently cannot establish a connection with Base Stations (BSs), which further complicates the joint satellite-BS connection and channel allocation. SF redistribution techniques based on Deep Reinforcement Learning (DRL) have been devised, taking into account the randomness of the data received by the terminal. In order to predict the best capacity improvements in the wireless instruments of 5G and 6G IoT networks, a hybrid algorithm for deep learning is being used in this study. To control the level of congestion within a 5G/6G network, the suggested approach is put into effect to a training set. With 0.933 accuracy and 0.067 miss rate, the suggested method produced encouraging results.

• 한국정보처리학회논문지
• /
• 제6권5호
• /
• pp.1342-1350
• /
• 1999

A new design procedure for micro cellular coverage prediction is presented here on this paper, which contains a new propagation analysis algorithm based on processing of vector data representing roads and buildings which mainly affect the propagation phenomena in micro-cell environments. The propagation analysis algorithm presented here has been developed to aim at the practical application for micro-cellular systems such as PCS or CE-2. As all the vectors used here are of closed poly lines, i.e., polygons, a simplified ray path search technique can be developed not only to determine if the calculation points are on the road polygons and but also to calculate the amount of blockage by buildings. The result shows a capability of predicting path loss with an RMS error of 5dB or lower.

• Nuclear Engineering and Technology
• /
• 제52권1호
• /
• pp.51-58
• /
• 2020

Despite the recent growth of interest in molten salt reactor technology and the crucial role which heat transfer plays in the design of power reactors, specific studies on the design of heat exchangers for the Molten Salt Fast Reactor have not yet been performed. In this work we deliver a preliminary but quantitative analysis of the intermediate heat exchangers, based on reference design data from the SAMOFAR H2020-Euratom project. Two different promising reference technologies are selected for study thanks to their compactness features, the Printed Circuit and the Helical Coil heat exchangers. We present preliminary design results for each technology, based on simplified design tools. Results highlight the limiting effects of the compactness constraints imposed on the fuel salt inventory and the allowed size. Large pressure drops on both flow sides are to be expected, with negative consequences on pumping power and natural circulation capabilities. The small size required for the flow channels also represents possible fabrication issues and safety concerns regarding channel blockage.

• 대한기계학회논문집B
• /
• 제25권11호
• /
• pp.1518-1526
• /
• 2001

In this paper, the mechanism of unsteady potential interaction and wake interaction in one stage axial turbine is numerically investigated at design point in two-dimensional viewpoint. The numerical technique used is the upwind scheme of Van-Leer's Flux Vector Splitting (FVS) and Cubic spline interpolation is applied on zonal interface between stator and rotor. The inviscid analysis is used to embody the influence of potential interaction only and viscous analysis is used to embody the influences of both potential interaction and wake interaction at the same time. The potential-flow disturbance from the stator into a rotor passage and the periodic blockage effect of rotor produce the unsteady pressure on the blade surface in inviscid analysis. After the wake is cut by rotor, two counterrotating votical patterns flanking the wake centerline in the passage are generated. So, these phenomena magnify the unsteady pressure in viscous analysis than that in inviscid analysis. The resulting unsteady forces on the rotor, generated by the combined interaction of the two effects by potential and wake interaction, are discussed.

• 한국산업정보학회논문지
• /
• 제27권1호
• /
• pp.111-123
• /
• 2022

코로나19 판데믹 상황에서 컨테이너선 운임은 유례없는 큰 폭의 상승세를 보이고 있다. 컨테이너선 운임 상승 요인에 대해서 다양한 분석이 이루어지고 있으나, 비정형 데이터인 텍스트 자료를 활용한 분석은 전무한 상황이다. 따라서 본 연구에서는 관련 기사들을 대상으로 최근의 컨테이너선 운임 상승의 요인들을 텍스트 마이닝 기법중 하나인 네트워크 텍스트 분석과 LDA 토픽 모델링을 통해 파악하였다. 2020년 1월부터 2021년 7월까지 로이즈리스트에 게재된 기사들을 대상으로 텍스트 분석을 하였다. 분석 결과, 중국과 미국의 무역마찰, 글로벌 생산감소를 예측한 글로벌 선사들의 급격한 기항 횟수의 감소와 임시결항의 증가, 터미널 혼잡, 수에즈 운하 봉쇄와 같은 예기치 못한 사고들이 주요 원인으로 분석되었다.

• 대기
• /
• 제24권1호
• /
• pp.77-87
• /
• 2014

The radar reflectivity is significantly affected by ground clutter, beam blockage, anomalous propagation (AP), birds, insects, chaff, etc. The quality of radar reflectivity is very important in quantitative precipitation estimation. Therefore, Weather Radar Center (WRC) of Korea Meteorological Administration (KMA) employed two quality control algorithms: 1) Open Radar Product Generator (ORPG) and 2) fuzzy quality control algorithm to improve quality of radar reflectivity. In this study, an occurrence of AP echoes and the performance of both quality control algorithms are investigated. Consequently, AP echoes frequently occur during the spring and fall seasons. Moreover, while the ORPG QC algorithm has the merit of removing non-precipitation echoes, such as AP echoes, it also removes weak rain echoes and snow echoes. In contrast, the fuzzy QC algorithm has the advantage of preserving snow echoes and weak rain echoes, but it eliminates the partial area of the contaminated echo, including the AP echoes.

• Nuclear Engineering and Technology
• /
• 제54권1호
• /
• pp.138-151
• /
• 2022

Cladding ballooning and rupture are the important phenomena at the early stage of a severe accident. Most severe accident analysis codes determine the cladding rupture based on simple parameter models. In this paper, a FRTMB module was developed using the thermal-mechanical model to analyze the fuel mechanical behavior. The purpose is to judge the cladding rupture with the severe accident analysis code. The FRTMB module was integrated into the self-developed severe accident analysis code ISAA to simulate the PHEBUS FPT3 experiment. The predicted rupture time and temperature of the cladding were basically consistent with the measured values, which verified the correctness and effectiveness of the FRTMB module. The results showed that the rising of gas pressure in the fuel rod and high temperature led to cladding ballooning. Consequently, the cladding hoop strain exceeded the strain limit, and the cladding burst. The developed FRTMB module can be applied not only to rod-type fuel, but also to plate-type fuel and other types of reactor fuel rods. Moreover, the FRTMB module can improve the channel blockage model of ISAA code and make contributions to analyzing the effect of clad ballooning on transient and subsequent parts of core degradation.

• Journal of Korean Biological Nursing Science
• /
• 제25권4호
• /
• pp.243-253
• /
• 2023

Purpose: This study conducted a concept analysis to clarify the meaning of anxiety in hospitalized patients with infectious diseases who have been placed in isolation. Methods: This study used Walker and Avant's process of concept analysis. Results: Anxiety in hospitalized patients with infectious diseases who have been placed in isolation can be defined by the following attributes: 1) fear, 2) guilt, 3) isolation, 4) discrimination, 5) frustration, 6) shame, and 7) uncertainty. The antecedents of anxiety were as follows: 1) a lack of information about infectious diseases, 2) restrictions of movement, 3) blockage of the social support system, 4) helplessness, and 5) negative biases. The consequences of anxiety were 1) internalized stigma, 2) loss of confidence, 3) lack of social activities and avoidance, 4) insomnia, 5) poor quality of life. Conclusion: The definition and attributes of anxiety identified in this study can be applied to enhance the understanding of anxiety in hospitalized patients with infectious diseases who have been placed in isolation. Systematic suppose should also be provided to reduce anxiety in these patients.

• ETRI Journal
• /
• 제35권5호
• /
• pp.775-785
• /
• 2013

Because of their exclusive features, millimeter wave directive mesh networks can be considered for small cell backhaul support in urban environments. For this purpose, a network of closely spaced stations has been considered with very directive line-of-sight links operating in the 60-GHz band. An attempt is made to evaluate channel response and interference behavior in such a network, taking into account the effect of building blockage. A simple grid of building blocks is considered as the propagation environment, and wave propagation is simulated using 2.5-dimensional (2.5D) ray tracing (2D with ground effect) to calculate the received signal at different nodes in the network. The results are compared with free space predictions and used to evaluate interference at all nodes in the channel and describe certain characteristics of links, such as the delay profile and the correlation length.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 추계학술대회 초록집
• /
• pp.149.1-149.1
• /
• 2010

가스 하이드레이트는 작은 고체 부피 내에 막대한 양의 가스를 저장할 수 있다는 특징으로 인하여 최근 주목을 받고 있지만, 엔지니어링 분야에서는 천연가스 수송 파이프라인에 blockage problem을 일으키는 해로운 물질로 처음 관심을 받았다. 이러한 문제를 해결하기 위한 방법으로 초기에는 하이드레이트 형성영역을 벗어나도록 온도, 압력을 유지하기도 하였으나, 최근에는 다양한 형성 억제제가 사용되고 있다. 본 연구에서는 기존에 억제제로 알려져 있는 대표적인 알코올 화합물인 에탄올을 이용하여 고압의 메탄과 binary 하이드레이트의 형성 연구를 수행하였다. 다양한 농도의 에탄올을 이용하여 형성된 하이드레이트 샘플은 고체 NMR 분석을 통하여 분자 거동을 자세히 측정하였으며, 분말 XRD 분석을 통하여 헝성된 미세 결정 구조도 확인하였다. 본 연구에서 얻어진 결과는 에탄올 및 알코올 화합물의 가스 하이드레이트 형성 거동 및 binary guest 시스템에서의 tuning 효과에 대한 유용한 정보를 제시할 수 있을 것이라 판단된다.