Mobility Performance Enhancement in Small Cells Cluster of 5G Network: A Handover Overhead Reduction Approach

Adeel Rafiq,Muhammad Afaq,Wang-Cheol Song 한국통신학회 2020 한국통신학회 APNOMS Vol.2020 No.09

To achieve high availability of traffic and maximum coverage in the 5G network, clusters of small cells approach to maximize the system capacity. In this approach, the Core Network (CN) encounters a large number of signals due to the frequent hand-off between small cells in the event of an increase in the speed of user movement and users within certain limits of small cells. The present 5G system executes all handoff signals in the traditional complex hierarchical sequence which leads the system toward the bad performance due to redundant signaling. NO Stack architecture has emerged as a promising methodology for radio access network (RAN) in the context of reducing the redundant signaling during X2-based handover by using control logic centrally and flat protocols. This paper proposes a system that is based on NO Stack architecture for reducing handoff requests in CN by assigning the dedicated mobility controller to each cluster of small cells for locally managing the mobility. The dedicated cluster controller specially designs to manage and control the cluster of small cells as well as maintain the forwarding information of user equipment locally. In this proposed system, the dedicated controller resides at the nearest edge cloud, therefore a distributed edge cloud network is developed for high computing infrastructure and low latency access for the X2-based handover request.

Measurement of Convective Heat Transfer Coefficients of Horizontal Thermal Screens under Natural Conditions

Adeel Rafiq(라피크아딜),Wook Ho Na(나욱호),Adnan Rasheed(라쉬드아드난),Hyeon Tae Kim(김현태),Hyun Woo Lee(이현우) (사)한국생물환경조절학회 2020 생물환경조절학회지 Vol.29 No.1

대류열전달은 겨울철 온실 열손실의 중요한 원인이 되며, 일반적으로 복사열에 의한 손실보다 더 크다. 스크린의 대류열전달계수를 자연상태에서 측정한 연구가 수행된 바는 있지만 상하면의 재질이 동일하고 공극이 없는 스크린에 대해서는 적용을 할 수 없는 방법이다. 이러한 재질의 스크린은 한국에서 많이 사용되고 있으나 대류열전달 특성을 파악하는데 많은 어려움이 있는 실정이다. 본 연구에서는 공극이 없는 3가지 종류의 스크린에 대해 대류열전달계수를 구하였으며, 계수를 산정하기 위하여 복사열수지 이론에 근거하여 산정방법을 개발하였다. 실험장치에 스크린을 설치하고 일사량, 장파복사량, 대기온도, 스크린 및 흑색천의 표면온도, 풍속 등을 측정하였다. 스크린의 표면온도와 주변온도의 차이에 따른 대류열전달계수를 산정하였다. 풍속이 거의 없는 상태에서 온도의 차이가 증가함에 따라 계수는 감소하는 것으로 나타났다. Convective heat transfer is the main component of greenhouse energy loss because the energy loss by this mechanism is greater than those of the other two components (radiative and conductive). Previous studies have examined the convective heat transfer coefficients under natural conditions, but they are not applicable to symmetric thermal screens with zero porosity, and such screens are largely produced and used in Korea. However, the properties of these materials have not been reported in the literature, which causes selectivity issues for users. Therefore, in this study, three screens having similar color and zero porosity were selected, and a mathematical procedure based on radiation balance equations was developed to determine their convective heat transfer coefficients. To conduct the experiment, a hollow wooden structure was built and the thermal screen was tacked over this frame; the theoretical model was applied underneath and over the screen. Input parameters included three components: 1) solar and thermal fluxes; 2) temperature of the screen, black cloth, and ambient air; and 3) wind velocity. The convective heat transfer coefficients were determined as functions of the air–screen temperature difference under open-air environmental conditions. It was observed from the outcomes that the heat transfer coefficients decreased with the increase of the air–screen temperature difference provided that the wind velocity was nearly zero.

NO-Stack Based Mobility Performance Enhancement by Reducing Core Network Signaling in Cluster of Small Cells for 5G Network

Adeel Rafiq,Wang-Cheol Song 한국통신학회 2019 한국통신학회 학술대회논문집 Vol.2019 No.6

Determination of Thermal Radiation Emissivity and Absorptivity of Thermal Screens for Greenhouse

rafiq adeel,나욱호,라쉬드아드난,김현태,이현우 (사) 한국생물환경조절학회 2019 생물환경조절학회지 Vol.28 No.4

Greenhouse farmers often use thermal screens to reduce greenhouse heating expenses during the winter, and for shade during hot, sunny days in the summer, as it is an inexpensive solution to temperature control relative to other available options. However, accurate measurements of their emitted and absorbed radiations are important for the selection of suitable screens that offer maximum performance. Material’s ability to save energy is highly dependent on these properties. Limited studies have investigated the measurement of these properties under natural conditions, but they are only applicable to materials having partial porosities. In this work, we describe a new radiation balance method for determining emissive power and absorptive capacity, as well as reflectivity, transmissivity and emissivity of materials having complete and partial transparency by using pyrgeometer and net radiometer. In this study, four materials with zero porosity, were tested. The emissivity value of PE, LD-13, LD-15 and PH-20 was 0.439±0.020, 0.460±0.010, 0.454±0.004, and 0.499±0.006, respectively. All tested samples showed high emitted radiation as compared to absorbed radiation.

Measurement of Long-Wave Radiometric Properties of Energy Saving Screens for Greenhouse

( Adeel Rafiq ),( Wook-ho Na ),( Adnan Rasheed ),( Hyun-woo Lee ) 한국농업기계학회 2019 한국농업기계학회 학술발표논문집 Vol.24 No.1

Appropriate climate screen can control the temperature and has the huge impact on the quantity and quality of crop. Precise measurement of long-wave radiative properties of screens are vital to select the suitable screen for greenhouse so that the desired temperature and the favorable environment can be provided to plants during night time. Energy saving of screens can also be calculated by giving these properties as an input in a physical model. In literature two approaches are available to measure these properties i.e. by using spectrophotometer and using wide-band radiometers. This study proposed a modified radiation balance method (PRBQ) for determining the total hemispherical long-wave radiative properties of screens by using wide-band radiometers. During this experiment one film and three screens were tested. Polyethylene (PE) film is used as reference material to verify the ability of the setup. Results showed similar radiometric values as given in the literature for polyethylene (PE) film.

Intent Based Networking for Optimized Resource Management using IBN Manager and Smart Path Manager

Rafiq Adeel,Diaz Rivera Javier,Wang-Cheol Song 한국콘텐츠학회 2018 한국콘텐츠학회 ICCC 논문집 Vol.2018 No.12

Determination of Thermal Radiation Emissivity and Absorptivity of Thermal Screens for Greenhouse

Adeel Rafiq,Wook Ho Na,Adnan Rasheed,Hyeon Tae Kim,Hyun Woo Lee (사)한국생물환경조절학회 2019 생물환경조절학회지 Vol.28 No.4

온실에서 겨울철 야간에는 열손실을 줄이기 위한 목적으로, 여름철 주간에는 차광을 위한 목적으로 스크린을 사용하고 있다. 온실의 냉난방 에너지 절감효과에 큰 영향을 미치는 스크린의 장파복사 방사율과 흡수 율은 온실에 설치할 적절한 스크린을 선택하는데 있어서 중요한 요소가 되며 이러한 특성값들을 정확하게 측 정할 수 있는 방법이 필요하다. 외부 환경조건에서 스크린의 장파복사 특성의 측정과 관련된 연구가 일부 수 행된 바 있지만 모든 종류의 스크린에 적용할 수 있는 방법은 아니고 공극이 있는 스크린 자재에만 적용이 가능한 방법이다. 본 연구에서는 순복사계 및 야간복사계를 사용하여 온실 스크린의 장파복사 흡수량과 방사량을 측정하고, 방사율, 흡수율 및 투과율을 결정하는 새로운 방법을 제시하였다. 특성값의 측정은 공극이 0인 4가 지 종류의 스크린 자재에 대하여 수행하였다. 모든 자재가 장파복사 방사량이 흡수량보다 높게 나타났다. PE, LD-13, LD-15 and PH-2의 장파복사 방사율은 각각 0.439±0.020, 0.460±0.010, 0.454±0.004, and 0.499±0.006 범위로 나타났다. Greenhouse farmers often use thermal screens to reduce greenhouse heating expenses during the winter, and for shade during hot, sunny days in the summer, as it is an inexpensive solution to temperature control relative to other available options. However, accurate measurements of their emitted and absorbed radiations are important for the selection of suitable screens that offer maximum performance. Material’s ability to save energy is highly dependent on these properties. Limited studies have investigated the measurement of these properties under natural conditions, but they are only applicable to materials having partial porosities. In this work, we describe a new radiation balance method for determining emissive power and absorptive capacity, as well as reflectivity, transmissivity and emissivity of materials having complete and partial transparency by using pyrgeometer and net radiometer. In this study, four materials with zero porosity, were tested. The emissivity value of PE, LD-13, LD-15 and PH-20 was 0.439±0.020, 0.460±0.010, 0.454±0.004, and 0.499±0.006, respectively. All tested samples showed high emitted radiation as compared to absorbed radiation.

Distributed SDN Based Network State Aware Architecture for Flying Ad-hoc Network

Muhammad Saqib,Asif Mehmood,Adeel Rafiq,Afaq Muhammad,Wang-Cheol SONG 한국통신학회 2020 한국통신학회 APNOMS Vol.2020 No.09

Flying networks are resource constraints while the nature of nodes’ mobility is very dynamic and unpredicted. Therefore, these networks are very prone to link failure and performance degradation. By considering the existing limitations, this work proposes a new approach consists of proactive and reactive network failure mitigation techniques that have been named as a hybrid approach. In the proposed architecture, the SDN controllers are distributed where each one controls its local domain nodes. The controller node continuously monitors the network state information and proactively adjusts the near-future changes to the topology. Each local domain also contains a sink node that directly connects to the controller. The sink node is used to forward the network state information to the controller and keep the controller defined flow rules for local domain nodes. The sink node can also request a new path in case of any link failure or any topology updates cause by nodes’ movement. Besides, a distributed routing protocol also runs on domain nodes to establish connectivity toward the sink node.

Generic Intent-Based Networking approach for end-to-end Slice Orchestration and Lifecycle Management

Talha Ahmed Khan,Muhammad Afaq,Khizar Abbas,Adeel Rafiq,Asif Mehmood,Wang-Cheol Song 한국통신학회 2020 한국통신학회 학술대회논문집 Vol.2020 No.2