Online Boundary Estimation in Partially Observable Environments Using a UAV

Newaz, Abdullah Al Redwan,Jeong, Sungmoon,Chong, Nak Young Springer-Verlag 2018 JOURNAL OF INTELLIGENT AND ROBOTIC SYSTEMS Vol.90 No.3

Evaluating Energy Efficiency of ONUs Having Multiple Power Levels in TDM-PONs

Newaz, S. H. S.,Cuevas, A.,Gyu Myoung Lee,Crespi, N.,Jun Kyun Choi IEEE 2013 IEEE COMMUNICATIONS LETTERS Vol.17 No.6

<P>A TDM Passive Optical Network (TDM-PON) proposes the use of sleep modes for Optical Network Units (ONUs) to maximize Energy Efficiency (EE). When an ONU manages a sleep mode, it needs to turn on and off some of its components based on communication requirements. Hence, an ONU ends up with multiple power levels. Existing analytical models for evaluating EE consider that an ONU has only two power levels. However, we have found in some literature where an ONU can have more than two power levels. In this letter we propose an analytical model to quantify the EE of an ONU having more than two power levels. We demonstrate the accuracy of the model by means of simulation under two different sleep interval deciding algorithms.</P>

UAV-based multiple source localization and contour mapping of radiation fields

Redwan Newaz, Abdullah Al,Jeong, Sungmoon,Lee, Hosun,Ryu, Hyejeong,Chong, Nak Young Elsevier 2016 Robotics and autonomous systems Vol.85 No.-

<P><B>Abstract</B></P> <P>This paper proposes an efficient approach to the multiple source localization and contour mapping problem of radiation fields using Unmanned Aerial Vehicles (UAVs). A typical radiation field originating from a single hotspot can be generated by three spatial distributions of sources; scattered, clustered and biased. Of these, the clustered sources are relatively easy to localize, because the sources are located in a close proximity to the center of distribution. In other cases, it is not very straightforward, because, when multiple radiating sources generate a hotspot in a cumulative manner, sources do not coincide with the hotspot position. Regardless of our knowledge about the hotspot position, we attempt to solve the multiple radiation localization problem in two steps: the Region Of Interest (ROI) selection and the source localization. Existing algorithms eventually explore whole area, causing the problem of excessive use of UAV resources. We therefore propose a framework to reduce ROI in a radiation field that not only optimizes the resources but also increases the localization accuracy. For the source localization process, two different methods are employed interchangeably. Those methods are called the Hough Transform and the Variational Bayesian, adaptively selected with a switching technique and the overall performance is evaluated by balancing between the localization accuracy and the required exploration. In favor of the optimization, the prediction model defines the type of sources in a way that the adaptive switching methodology can converge to an optimal solution by selecting an appropriate method. Thus, the proposed framework enables the UAV to accurately localize the radiation sources in a fast manner. In order to verify the validity and the performance of the proposed strategies, we performed extensive numerical experiments with different numbers of sources and their positions. Our empirical results clearly show that the proposed approach outperforms existing individual approaches.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A framework is proposed that enables a single UAV to accurately localize the radiation sources in a fast manner. </LI> <LI> In an unknown radiation field, we attempt to solve the multiple radiation localization problem in two steps. </LI> <LI> By reducing the ROI in a radiation field, we not only optimize the resources but also are able to increase the localization accuracy. </LI> <LI> By employing two different methods interchangeably, we are able to balance between the localization accuracy and exploration constraints. </LI> </UL> </P>

Evaluation of heavy metal pollution risk associated with road sediment

Kazi Kader Newaz,Sudip Kumar Pal,Shahadat Hossain,Ahasanul Karim 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.3

A detailed investigation has been conducted to assess the heavy metal pollution risk associated with the road deposited sediment collected from the 32 major road sites in Chittagong city. The acid digestion of road sediments for metals extraction was carried out prior to determine total concentrations of Zn, Pb, Cr, Cu, Ni, Cd by using Polarized Zeeman Atomic Absorption Spectrophotometer (Z-2000) following standard analytical protocol. The contamination and pollution risk level were assessed using degree of contamination, potential ecological risk index and integrated pollution index. The study revealed that the mean heavy metal concentrations of Zn, Pb, Cr, Cu, Ni, Cd were found as 975, 84, 77, 74, 32, 1.6 ㎎/㎏, respectively, across the road sites in Chittagong city. The mean concentrations are found 1.1 to 44 times higher in comparison to soil background, signifying relatively greater enrichment for Zn, Cd and Pb across the sites, suggesting vehicular emission on roads with site-specific characteristics. Based on pollution indices, Ruby Cement, City Gate and Enayeth Bazar road sites pose high risk, while eight other sites are found with moderate to considerable risk potential, and remaining 21 sites pose low to moderate risk potential.

Early wake-up decision algorithm for ONUs in TDM-PONs with sleep mode

Mohammed, Alaelddin Fuad Yousif,Newaz, S. H. Shah,Uddin, Mohammad Rakib,Lee, Gyu Myoung,Choi, Jun Kyun IEEE 2016 Journal of optical communications and networking Vol.8 No.5

<P>Recent IEEE and ITU-T standards for time division multiplexing-passive optical networks (TDM-PONs) with sleep mode recommend that the optical line terminal (OLT) in a TDM-PON should be in charge of invoking the optical network units (ONUs) to move into the sleep state in the absence of frames. It is considered that, upon upstream frame arrival, a sleeping ONU can leave the sleep state, in which an ONU turns off its transmitter or both its transmitter and receiver, immediately, prior to its assigned sleep interval length. In this paper, we refer to this approach as immediate early wake-up (IMEW). According to the standards, the OLT may or may not allow an ONU to trigger an early wake-up function (EWF) upon the upstream frames' arrival. If the OLT does not allow the EWF [we refer to this as not support early wake-up (NSEW)], an ONU should stay in the sleep state during its assigned sleep duration and buffer all the upstream frames while it is in this state. In IMEW, the upstream frames experience a small delay, but the ONU's energy consumption increases remarkably. Conversely, in NSEW, an ONU consumes less energy compared to IMEW at the price of increasing the upstream frame delay and the possibility of having its buffer overflow. In this paper, the limitations of IMEW and NSEW have motivated us to propose a novel early wake-up decision (EWuD) algorithm that aims at meeting the upstream frame delay requirement while reducing the ONUs' energy consumption as much as possible. The role of the EWuD algorithm is to select an appropriate time for triggering EWF, taking into consideration two factors: 1) buffer overflow probability and 2) delay requirement violation of upstream frames. We evaluate EWuD performances using our TDM-PON OPNET modular-based simulation model under a wide range of scenarios. The findings demonstrate that our proposed EWuD can successfully meet the delay requirements of all upstream frames while reducing the ONUs' energy consumption significantly.</P>

Genotype-Environment Interaction and Stability Analysis for Yield and Yield Contributing Characters in Soybean(Glycine max L.)

Islam, Mohammad Saiful,Newaz, Muhammad Ali,Islam, Md. Jahidul,Heo, Seong-Il,Wang, Myeong-Hyeon The Plant Resources Society of Korea 2007 한국자원식물학회지 Vol.20 No.6

GE interaction is the expression of differential genotypic adaptation across environments. GE interactions through different stability parameters and performance of the traits of genotypes were studied. The traits were days to maturity, pod length, number of pods/ plant, 100-seed weight and seed yield/plant in ten soybean genotypes across five environments. Significant differences were observed for genotypes, environments and GE interactions. Stability analysis after Eberhart and Russell's model suggested that the genotypes used in this study were all more or less responsive to environmental changes. Most of the genotypes perform better in Env.3. Based on phenotypic indices(Pi), regression ($S^2di$) genotype Garurab was found fairly stable for days to maturity. BS-23 and G-2120 may be considered as stable genotype for pod length. All the genotypes except G-2120 showed that the genotypes were relatively unstable under environmental fluctuation for the number of pod/plant. Genotype BS-23 was found most stable among all the genotypes for 100-seed weight. BS-3 and Gaurab was the most stable and desirable genotypes for seed yield in soybean.

Human Rights-Based Approach to Science, Technology and Development: A Legal Analysis

Ridoan Karim,Md S. Newaz,Rafsan M. Chowdhury 이준국제법연구원 2018 Journal of East Asia and International Law Vol.11 No.1

The nexus between science and human rights are intertwined in many ways. Though the acknowledgment in international law have been available for decades, the right to savor the fruits of scientific advancement and its applicability has gained just small recognition of the human rights from the international community. A human rightsbased approach to science, technology, and development endeavors a concern for human rights at the heart of the international community facing with critical global challenges. Thus, the paper initially discusses the relevant international human rights instruments including laws, regulations, declarations, conventions and provides a thorough analysis. The doctrinal and qualitative study of the paper presents human rights approaches in order to show insight on the ethical implications of new technologies and investigate how policy can compete with briskly advancing science. The paper also recommends the international community to promote regulatory processes that can help in blocking the disputes by securing an equilibrium between human rights and science.

Computational investigation of the post-yielding behavior of 3D-printed polymer lattice structures

Fadeel Abdalsalam,Abdulhadi Hasanain,Newaz Golam,Srinivasan Raghavan,Mian Ahsan 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.1

Sandwich structures are widely used due to their light weight, high specific strength, and high specific energy absorption. Three-dimensional (3D) printing has recently been explored for creating the lattice cores of these sandwich structures. Experimental evaluation of the mechanical response of lattice cell structures (LCSs) is expensive in time and materials. As such, the finite element analysis (FEA) can be used to predict the mechanical behavior of LCSs with many different design variations more economically. Though there have been several reports on the use of FEA to develop models for predicting the post-yielding stages of 3D-printed LCSs, they are still insufficient to be a more general purpose due to the limitations associated with the lattice prediction behavior of specific features, certain geometries, and common materials along with showing sometimes poor prediction due to the computationally cheap elements out of which these models have been composed in most cases. This study focuses on the response of different LCSs at post-yielding stages based on the hexahedral elements to capture accurately the behaviors of 3D-printed polymeric lattices made of the Acrylonitrile Butadiene Styrene material. For this reason, three types of lattices such as body centered cubic, tetrahedron with horizontal struts, and pyramidal are considered. The FEA models are developed to capture the post-yielding compressive behavior of these different LCSs. These models are used to understand and provide detailed information of the failure mechanisms and relation between post-yielding deformations and the topologies of the lattice. All of these configurations were tested before experimentally during compression in the z-direction under quasi-static conditions and are compared here with the FEA results. The post-yielding behavior obtained from FEA matches reasonably well with the experimental observations, providing the validity of the FEA models.

Grant management procedure for energy saving TDM-PONs

Alaelddin, Fuad Yousif Mohammed,Newaz, S.H. Shah,AL-Hazemi, Fawaz,Choi, Jun Kyun Elsevier 2018 Optical fiber technology Vol.40 No.-

<P><B>Abstract</B></P> <P>In order to minimize energy consumption in Time Division Multiplexing-Passive Optical Network (TDM-PON), IEEE and ITU-T have mandated sleep mode mechanism for Optical Network Units (ONUs) in the latest TDM-PON standards (e.g. IEEE P1904.1 SIEPON, ITU-T G.sup45). The sleep mode mechanism is a promising mean for maximizing energy saving in an ONU. An ONU in sleep mode flips between <I>sleep</I> and <I>active state</I> depending on the presence or absent of upstream and downstream frames. To ensure Quality of Service (QoS) of upstream frames, the recent TDM-PON standards introduced an early wake-up mechanism, in which an ONU is forced to leave the <I>sleep state</I> on upstream frame arrival. When the Optical Line Terminal (OLT) of a TDM-PON allows early wake-up of its connected ONUs, it allocates gratuitous grants for the sleeping ONUs along with allocating upstream grants for the ONUs in <I>active state</I>. Note that, the gratuitous grants control message sent periodically by the OLT on Inter-Gratuitous grant Interval (IGI) time. After leaving <I>sleep state</I> due to the arrival of upstream frame, the ONU uses its allocated gratuitous grant to send a control message mentioning the amount of upstream bandwidth (upstream grant) required in order to forward the remaining frames in its buffer. However, the existing early wake-up process of ONU can lead to increase the energy consumption of an ONU. It is because of the ONU wakes-up immediately from the <I>sleep state</I> on arrival of the upstream frame, but even so, it needs to wait for forwarding the frame until its allocated gratuitous grant period, resulting in spending energy unnecessarily. In addition, current energy saving solution for TDM-PONs do not provide a clear solution on how to manage different types of grants (e.g. listening grant, upstream transmission grant) within a Dynamic Bandwidth Allocation (DBA) polling cycle. To address this problem, we propose a state-of-art Grant Management Procedure (GMP) in order to maximize energy saving in a TDM-PON with sleep mode enabled ONUs. GMP contributes in defining the location of the different types of grants during a DBA polling cycle. Furthermore, GMP devises a mechanism so as to allow an ONU to predict its assigned gratuitous grant control message arrival time, thereby allowing an ONU to remain its transceiver unit powered off until the arrival period of the next gratuitous grant control message, increasing the energy saving of the ONU. Results show that, with the increment of IGI, the energy saving performance of an ONU with GMP increases noticeably in compare to a conventional ONU (an ONU that does not use GMP) without imposing any additional upstream frame delay.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First effort dedicated to arrange different types of grants during a DBA cycle. </LI> <LI> We proposed a state-of-art Grant Management Procedure (GMP). </LI> <LI> GMP maximizes the energy saving in TDM-PONs with sleep mode enabled ONUs. </LI> <LI> ONUs utilizing GMP can predict gratuitous grant control message arrival time. </LI> </UL> </P>

Towards improving throughput and reducing latency: A simplified protocol conversion mechanism in distributed energy resources network

Yoo, Yoon-Sik,Newaz, S.H. Shah,Shannon, Peter David,Lee, Il-Woo,Choi, Jun Kyun Elsevier 2018 APPLIED ENERGY Vol.213 No.-

<P><B>Abstract</B></P> <P>With our research on communicating entities in heterogeneous Distributed Energy Resources (DERs), which utilize both IEC 61850 and other legacy interfaces, we show two things: firstly, (1) how the commonly deployed methods of achieving interoperability between incompatible interfaces can be altered to optimize throughput and latency; secondly, (2) how large an effect the optimization has by quantifying delay and throughput for the common method and our new method introduced in this paper.</P> <P>A prime objective of DERs is to enhance efficiency, stability and safety management during an emergency. Timely availability of operational data on DER entities in remote management centers will allow management software to extend the capabilities of, for example, an emergency generator to predict and correct for failure or operate more efficiently in a DER with mix of energy production types (solar, wind, petrol and so on). A DER often integrate a variety of entities which have proprietary incompatible interfaces (e.g. Modbus, DNP3, RS-485 and IEC 60870). To facilitate interoperability a protocol conversion mechanism is necessary. Here we concentrate on communication between the relatively modern IEC 61850, and Modbus, the most common proprietary interface.</P> <P>For our research, we built a new entity which integrates two other entities which are normally separate devices in a DER: a DER Management Server (DER-MS) and Modbus Feeder Master (MFM). Consolidating these two entities into a single box allows us to replace network inter-process communication with local inter-process communication, eliminating significant time sending messages from the remote management centers to peripheral elements in a DER (e.g. emergency generators) and back again. Using the same DER, we quantified network delay and throughput for: (a) our newly built simplified protocol conversion device and (b) the common configuration with MFM and DER-MS. We tested both configurations by benchmarking data requests from a remote management center to an emergency generator. Latency and throughput results obtained through experiment demonstrate that, our solution outperforms the common configuration with MFM and DER-MS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This solution facilitates interoperability between Modbus and IEC 61850. </LI> <LI> This solution reduces delay around 40%, compared to the existing solution. </LI> <LI> This solution increases throughput around 40%, compared to the existing solution. </LI> <LI> This solution reduces delay variance by 0.35 ms, compared to the existing solution. </LI> <LI> Proposed solution is expected to be cost effective and more reliable. </LI> </UL> </P>