Study of Challenges in Implementing Digital Transformation in Construction Projects

The main objective of this paper is to identify the challenges in implementing digital transformation in construction projects. Digital transformation is vital for construction projects due to its many benefits including increased productivity and an improved collaborative environment. A literature review was conducted to study the existing publications on digital transformation to identify the possible challenges and barriers that affect the construction industry transformation. Papers published from 2019 to 2021 were studied for this literature review with the objective of finding the latest knowledge on this topic. This paper identifies challenges and barriers in the construction sector as well as solutions to overcome the possible challenges. Digital transformation phases, processes and resources are discussed in this paper.  This study also identified gaps and future research areas to obtain more accurate data regarding the challenges in digital transformation in construction projects

Resource allocation for heterogeneous wireless networks

Demand for high volumes of mobile data traffic with better quality-of-service (QoS) support and seamless network coverage is ever increasing, due to growth of the number of smart mobile devices and the applications that run on these devices. Also, most of these high volumes of data traffic demanding areas are covered by heterogeneous wireless networks, such as cellular networks and wireless local area networks (WLANs). Therefore, interworking mechanisms can be used in these areas to enhance the network capacity, QoS support and coverage. Interworking enhances network capacity and QoS support by jointly allocating resources of multiple networks and enabling user multi-homing, where multi-homing allows users to simultaneously communicate over multiple networks. It widens network coverage by merging coverage of individual networks. However, there are areas where interworking cannot improve network capacity or QoS support, such as the areas with coverage of only one networks. Therefore, to achieve network-wide uniform capacity and QoS support enhancements, interworking can be integrated with device-to-device (D2D) communication and small cell deployment techniques. One of the challenging issues that need to be solved before these techniques can be applied in practical networks is the efficient resource allocation, as it has a direct impact on the network capacity and QoS support. Therefore, this thesis focuses on studying and developing efficient resource allocation schemes for interworking heterogeneous wireless networks which apply D2D communication and small cell deployment techniques. First, uplink resource allocation for cellular network and WLAN interworking to provide multi-homing voice and data services is investigated. The main technical challenge, which makes the resource allocation for this system complicated, is that resource allocation decisions need to be made capturing multiple physical layer (PHY) and medium access control layer (MAC) technologies of the two networks. This is essential to ensure that the decisions are feasible and can be executed at the lower layers. Thus, the resource allocation problem is formulated based on PHY and MAC technologies of the two networks. The optimal resource allocation problem is a multiple time-scale Markov decision process (MMDP) as the two networks operate at different time-scales, and due to voice and data service requirements. A resource allocation scheme consisting of decision policies for the upper and the lower levels of the MMDP is derived. To reduce the time complexity, a heuristic resource allocation algorithm is also proposed. Second, resource allocation for D2D communication underlaying cellular network and WLAN interworking is investigated. Enabling D2D communication within the interworking system further enhances the spectrum efficiency, especially at areas where only one network is available. In addition to the technical challenges encountered in the first interworking system, interference management and selection of users' communication modes for multiple networks to maximize hop and reuse gains complicate resource allocation for this system. To address these challenges, a semi-distributed resource allocation scheme that performs mode selection, allocation of WLAN resources, and allocation of cellular network resources in three different time-scales is proposed. Third, resource allocation for interworking macrocell and hyper-dense small cell networks is studied. Such system is particularly useful for interference prone and high capacity demanding areas, such as busy streets and city centers, as it uses license frequency bands and provides a high spectrum efficiency through frequency reuse and bringing network closer to the users. The key challenge for allocating resources for this system is high complexity of the resource allocation scheme due to requirement to jointly allocate resources for a large number of small cells to manage co-channel interference (CCI) in the system. Further, the resource allocation scheme should minimize the computational burden for low-cost small cell base stations (BSs), be able to adapt to time-varying network load conditions, and reduce signaling overhead in the small cell backhauls with limited capacity. To this end, a resource allocation scheme which operates on two time-scales and utilizes cloud computing to determine resource allocation decisions is proposed. Resource allocation decisions are made at the cloud in a slow time-scale, and are further optimized at the BSs in a fast time-scale in order to adapt the decisions to fast varying wireless channel conditions. Achievable throughput and QoS improvements using the proposed resource allocation schemes for all three systems are demonstrated via simulation results. In summary, designing of the proposed resource allocation schemes provides valuable insights on how to efficiently allocate resources considering PHY and MAC technologies of the heterogeneous wireless networks, and how to utilize cloud computing to assist executing a complex resource allocation scheme. Furthermore, it also demonstrates how to operate a resource allocation scheme over multiple time-scales. This is particularly important if the scheme is complex and requires a long time to execute, yet the resource allocation decisions are needed to be made within a short interval

Job Satisfaction and Job Performance of the Sailors in Rapid Action BoatSquadron of Sri Lanka Navy

This paper aims at empirically investigating job satisfaction on job performance of thesailors in Rapid Action Boat Squadron in Sri Lanka Navy. Data were collected from 219sailors using Minnesota Satisfaction Questionnaire (MSQ) and the structured questionnairedeveloped by Udayakumar (2003) was used for measuring job performance. PearsonCorrelation Coefficient and Curve Fit Analysis were employed for the analysis of data. Thestudy substantiated that there is a fairly positive relationship between job satisfaction and jobperformance of the sailors. The results suggest that the satisfaction aspect on its own doesnecessarily lead to improved individual performance and assumedly organizationaleffectiveness. Therefore, it needs to implement satisfaction-performance model effectivelythrough specific practices. The paper empirically investigated satisfaction-performancemodel in Rapid Action Boat Squadron of Sri Lanka Navy context and offers practicalimplications for top level administration of the Squadron seeking effective implementation ofthe satisfaction-performance model.Key Word(s) : Job Satisfaction, Job Performance, Rapid Action Boat Squadron of Sri LankaNav

ONE-WAY END-TO-END PATH DELAY MEASUREMENT FOR SR/SRV6 TRAFFIC ENGINEERING POLICIES WITHOUT CLOCK SYNCHRONIZATION IN SOFTWARE DEFINED NETWORKS

Solutions are described herein that provide for one-way end-to-end path delay measurements for Segment Routing (SR) and SR with IPv6 (SRv6) Traffic Engineering (TE) policies without clock synchronization in Software Defined Networks (SDNs). A centralized solution is provided using a controller while a distributed solution is provided without using a controller

Effect of nucleation sites on the growth and quality of single-crystal boron arsenide

Boron arsenide (BAs) has been the least investigated cubic III-V compound, but it has recently attracted significant attention since the confirmation of its unusually high thermal conductivity above 1000 W/m-K. However, determining how to achieve growth of a BAs single crystal on the centimeter scale remains unsolved, which strongly limits further research into, and potential applications of, this interesting material. Here we report our technique to grow a 7-mm-long BAs single crystal via the chemical vapor transport method by applying an additional nucleation site. The different thermal conductivity values obtained from BAs single crystals grown on nucleation sites of different compositions show the importance of choosing the proper nucleation-site material. We believe these findings will inspire further research into the growth of this unique semiconductor.Comment: 8 pages, 3 figure

Optical properties of cubic boron arsenide

The ultrahigh thermal conductivity of boron arsenide makes it a promising material for next-generation electronics and optoelectronics. In this work, we report measured optical properties of cubic boron arsenide crystals including the complex dielectric function, refractive index, and absorption coefficient in the ultraviolet, visible, and near-infrared wavelength range. The data were collected at room temperature using spectroscopic ellipsometry as well as transmission and reflection spectroscopy. We further calculate the optical response using density functional and many-body perturbation theory, considering quasiparticle and excitonic corrections. The computed values for the direct and indirect band gaps (4.25 eV and 2.07 eV) agree well with the measured results (4.12 eV and 2.02 eV). Our findings contribute to the effort of using boron arsenide in novel electronic and optoelectronic applications that take advantage of its demonstrated ultrahigh thermal conductivity and predicted high ambipolar carrier mobility

Identifying indicators of vulnerability from short speech segments using acoustic and textual features

In order to protect vulnerable people in telemarketing, organisations have to investigate the speech recordings to identify them first. Typically, the investigation is manually conducted. As such, the procedure is costly and time-consuming. With an automatic vulnerability detection system, more vulnerable people can be identified and protected. A standard telephone conversation lasts around 5 minutes, the detection system is expected to be able to identify such a potential vulnerable speaker from speech segments. Due to the complexity of the vulnerability definition and the unavailable annotated vulnerability examples, this paper attempts to address the detection problem as three classification tasks: age classification, accent classification and patient/non-patient classification utilising publicly available datasets. In the proposed system, we trained three sub models using acoustic and textual features for each sub task. Each trained model was evaluated on multiple datasets and achieved competitive results compared to a strong baseline (i.e. in-dataset accuracy)

Thermal expansion coefficient and lattice anharmonicity of cubic boron arsenide

Recent measurements of an unusual high thermal conductivity of around 1000 W m-1 K-1 at room temperature in cubic boron arsenide (BAs) confirm predictions from theory and suggest potential applications of this semiconductor compound for thermal management applications. Knowledge of the thermal expansion coefficient and Gr\"uneisen parameter of a material contributes both to the fundamental understanding of its lattice anharmonicity and to assessing its utility as a thermal-management material. However, previous theoretical calculations of the thermal expansion coefficient and Gr\"uneisen parameter of BAs yield inconsistent results. Here we report the linear thermal expansion coefficient of BAs obtained from the X-ray diffraction measurements from 300 K to 773 K. The measurement results are in good agreement with our ab initio calculations that account for atomic interactions up to fifth nearest neighbours. With the measured thermal expansion coefficient and specific heat, a Gr\"uneisen parameter of BAs of 0.84 +/- 0.09 is obtained at 300 K, in excellent agreement with the value of 0.82 calculated from first principles and much lower than prior theoretical results. Our results confirm that BAs exhibits a better thermal expansion coefficient match with commonly used semiconductors than other high-thermal conductivity materials such as diamond and cubic boron nitride