This article explores the power-sensitivity trade-off in optical receivers aiming to improve the energy-efficiency of the overall link. Optical receivers with field-effect transistor (FET) front-ends (FEs) are usually designed for optimal noise performance by matching the circuit’s input capacitance (CI) to the total input parasitic capacitance (CD) . However, the receiver’s power dissipation is also proportional to the input capacitance CI . Therefore, this paper studies the feasibility of the capacitive matching rule in the context of minimizing the power dissipation of the overall link. For that purpose, design trade-offs for the receiver, transmitter, and the overall link are presented. Comparisons are made to study how much the receiver can be downsized, sacrificing optimal noise performance, before its power reduction is offset by the transmitter’s increase in power. Simulation results show that energy-efficient links require low-power receivers with input capacitance much smaller than that required for noise-optimum performance. As an example, for a 25 Gb/s operation, an optical loss budget of 12.6 dB, and a receiver designed in 65 nm CMOS technology with CD of 200 fF, the overall link dissipates 2.55 pJ/bit when the receiver’s noise is minimized, leading to a receiver with CI/CD=1.29 . When optimized for overall link efficiency, the receiver size is significantly reduced to CI/CD=0.38 and the link’s energy-efficiency also improves to 1.41 pJ/bit. If the link budget or knowledge of the transmitter side is incomplete, our analysis indicates that maximizing gain with value of CI/CD=0.5 is a reasonable choice.

A smart controls system can control and optimize building services. This article aims to improve mosque energy efficiency. To ensure a comfortable environment, indoor temperatures, lighting performance, and illumination levels were monitored. DIAlux simulation software visualized the lighting for the indoor mosque environment. To assess the impact of smart occupancy sensors on total energy consumption, the DesignBuilder simulation tool was used. Mosque energy consumption can be significantly reduced. By replacing traditional lighting units inside mosques with LEDs, 9 % of the total energy could be saved. Utilizing a smart control plan with the mosque's energy index of 69 kWh/m²/yr could significantly reduce energy consumption. Since there are fewer prayers, except for Friday prayers and Ramadan, energy-regulating smart control systems are applicable during most prayer times. The study focuses on the mosque as a sustainable building and proposes a new concept for mosques to function as energy-efficient buildings in hot arid climate.

Off-site construction (OSC) is an innovative construction method that transfers most of the site-based work to a more controlled environment. Construction waste minimization, speedy schedules, higher sustainability, and better quality are some of the perceived benefits of OSC. Therefore, significant research attention has been given to OSC. However, minimal research attention has been given to procurement management in OSC, which could impact its pace of adoption. Existing studies on the procurement methods of OSC projects have overlooked several criteria related to OSC that impact the selection of the appropriate procurement methods (i.e., design-build, construction management, etc.). In addition, the literature lacks decision-making tools to assist OSC practitioners in selecting the appropriate procurement method. In this regard, this study contributes to the body of knowledge by (1) identifying the criteria that impact the selection of OSC procurement methods; (2) developing a multi-criteria decision-making (MCDM) model to select the appropriate OSC procurement methods. The developed MCDM model uses a hybrid approach of analytic network process (ANP) and evidential reasoning (ER). The ANP, which considers the interdependencies among the collected OSC procurement criteria, is used to calculate the relative importance weights through questionnaire surveys. The ER method evaluates various OSC procurement methods in accordance with the criteria importance weights. The results indicate that project quality, cost control, and funding arrangement are the prominent selection factors. On the other hand, the model reveals that the integrated project delivery (IPD) and construction management (CM) methods have the highest utility scores. The MCDM model has been validated by comparing the results with similar studies. The present study could assist OSC practitioners in selecting the appropriate procurement method for OSC projects.

Multimodal Freight Transport (MFT) has been introduced as a solution for reducing the external costs of freight transport while achieving cost improvements. Despite the MFT benefits, its share has been low in practice, and transport by trucks remains the most preferred transport mode. A few works have recently investigated this issue by discussing various barriers to MFT. However, little conceptual work comprehensively examines the barriers that organizations may face during MFT applications. To address this gap, this paper has reviewed 104 studies and identified 31 barriers and possible strategies for overcoming them. To clarify the nature of these barriers, we developed a conceptual barrier framework that positions the identified barriers within the overall MFT chain. This framework categorizes the barriers into six categories: MFT terminal, MFT network, management, regulations and subsidies, delivery characteristics, and interoperability. The findings provide decision-makers and practitioners with theoretical and practical insights into the barriers to transition toward MFT and will assist them in implementing MFT successfully.

Solar air heating (SAH) is a low-cost method for air heating using solar energy. An energy and exergy performance is performed experimentally on new designed tubular SAH having tubular absorber of adjacent tubes forming flat pack. Each tube of the absorber contains three adjacent internal tubes forming nabla shape (∇). The nabla tubular SAH (∇TSAH) performance is studied compared to ordinary tubular SAH (OTSAH) having tubular absorber only for single pass (SP) and double pass (DP) flow conditions and different mass flow rates of air (MFRA). The study is investigated under upper Egypt hot climate conditions and 0.018–0.081 kg/s MFRA. The results demonstrate that ∇TSAH has higher outlet air temperature, energy gain, higher energy, exergy, and thermohydraulic efficiencies, and lower top losses than the OTSAH. The new design boosts the exit air temperature by about 13.5 and 5 °C for SP and DP …

In this article, the spectrum trading problem between primary users and secondary networks is
investigated. The secondary network requests multiple channels with the targeted availability to satisfy its
users' demands. Due to the uncertainty about the channels availability, stochastic optimization techniques
are adopted to nd the optimal set of channels for each secondary network for the lowest cost. Two different
constraints on the secondary demand are dened. The rst one is when the throughput has to be fully satised
for a certain percentage of time, and the second one is when the expected value of the throughput has
to exceed a certain percentage of the requested one. Also, the possibility for channel subleasing among
the secondary networks is investigated to reduce the demand shortage. The results show that demanding
simultaneous channels increases the cost as it reaches up to 20% higher than if the same resources were
requested individually. Also, channels subleasing reduces the demand shortage probability and increases
the achieved throughput, especially at low value of requested demand. In this case, the demand satisfaction
probability increases by around 30% while the achieved throughput increases up to 40% compared to the
scenario where channels subleasing is not allowed.