Lightweight Neural Network-Based Viewport Prediction for Live VR Streaming in Wireless Video Sensor Network

Live virtual reality (VR) streaming (a.k.a., 360-degree video streaming) has become increasingly popular because of the rapid growth of head‐mounted displays and 5G networking deployment. However, the huge bandwidth and the energy required to deliver live VR frames in the wireless video sensor network (WVSN) become bottlenecks, making it impossible for the application to be deployed more widely. To solve the bandwidth and energy challenges, VR video viewport prediction has been proposed as a feasible solution. However, the existing works mainly focuses on the bandwidth usage and prediction accuracy and ignores the resource consumption of the server. In this study, we propose a lightweight neural network-based viewport prediction method for live VR streaming in WVSN to overcome these problems. In particular, we (1) use a compressed channel lightweight network (C-GhostNet) to reduce the parameters of the whole model and (2) use an improved gate recurrent unit module (GRU-ECA) and C-GhostNet to process the video data and head movement data separately to improve the prediction accuracy. To evaluate the performance of our method, we conducted extensive experiments using an open VR user dataset. The experiments results demonstrate that our method achieves significant server resource saving, real-time performance, and high prediction accuracy, while achieving low bandwidth usage and low energy consumption in WVSN, which meets the requirement of live VR streaming.

Multifunctional fiber-optic sensors for space infrastructure

Sensors used in rocket and space technology are subject to extreme external influences in terms of temperature, vibration, and shock. Therefore, the choice of the type of sensors is justified precisely by the resistance to such factors, as well as the ability to ensure the temporal and parametric stability of measurements. A new type of sensors – fiber-optic ones – meets these conditions. The basis for the selection and further improvement of such sensors were such requirements as minimum power consumption, high accuracy and stability of measurements, the ability to combine several measurements in one sensor. It is noted that for space infrastructure the factor of the possibility of simultaneous measurement of several parameters with one sensor is one of the important quality indicators. This is due to the possibility of reducing the number of sensors themselves, which reduces the mass and size parameters of space technology. This applies, first of all, to measurements of pressure and temperature, since they, in aggregate, account for at least 40 % of all measurements in space products. The path of choos-ing the types of methods and sensor designs led to the combination of the amplitude conversion method and optical communication in one sensor. In this case, amplitude modulation of pressure and temperature is carried out by a microelec-tromechanical unit (module), and the modulated optical signal is transmitted by an optical module. Such a modular composition of the sensor makes it possible to dispense with optical ana-lyzers (interrogators) and carry out further pro-cessing based on standard interfaces. A limitation of the proposed methods and designs is the need for microelectromechanical structures that measure certain physical quantities. Such structures for fiber-optic sensors are not mass-produced; therefore, their manufacture can be established at instrument-making enterprises with microelectronic equipment

Architectural building design with refurbished shipping containers: a typological and modular approach

Construction of housing buildings using refurbished shipping containers constitutes a successful recent building system. As construction modules, disposed and recycled containers are considered to contribute for a sustainable construction system. This article aims to contribute to a better understanding on this construction system, in particular the architectural project. A methodology based on the typological and modular coordination is proposed as a key tool to help for the development of spatial arrangements by considering the shipping container as a unit/module. The functional occupation typologies were proposed to characterize the main housing activities to be considered in modular coordinated design, allowing to adapt the housing to the family needs according to their social and cultural dynamics. The module constitution and geometry considering two commercial maritime shipping containers are presented.

STRATEGI PERANCANGAN DESAIN KERUANGAN HUNIAN VERTIKAL DI MASA PANDEMI COVID-19

The Covid-19 pandemic makes vertical housings vulnerable to mental health problems for residents. The cause of this problem is due to the small size of space, which is shrinking due to changes in urban patterns, which are not able to meet the needs of residents. The resident needs that are usually obtained outside the housing cannot be achieved due to social distancing or the lockdown. The closure of access also makes the residence must be able to become a place of work and entertainment space. As a result, the small dwellings are getting more and more cramped to live in. This problem encourages changes in new housing patterns that take into account the needs of each occupant. The use of a multidisciplinary approach by combining human psychology theory with architectural design theory is able to provide solutions in forming new residential patterns. Maslow's theory of human needs and Ray Oldenburg's theory of the Three Realms of Space form the basis of theory in designing. The design result is a residential unit module design that has all component place by Ray Oldenburg and fulfills Maslow's pyramid theory of needs. Key words: Covid-19 pandemic; Housing Pattern; Human Needs; Shrinking Space; Three Realms of Space AbstrakPandemi Covid-19 membuat hunian-hunian vertikal menjadi rentan terhadap permasalahan kesehatan mental penghuninya. Penyebab permasalahan ini dikarenakan ruang dengan ukuran kecil, yang menyusut akibat perubahan pola kota, yang tidak mampu memenuhi kebutuhan penghuni. Kebutuhan yang biasanya didapatkan di luar hunian menjadi tidak dapat dijangkau karena adanya social distancing hingga lockdown. Penutupan akses juga membuat hunian harus mampu beradaptasi menjadi tempat kerja dan tempat hiburan. Akibatnya hunian yang kecil semakin sesak untuk ditinggali. Permasalahan ini mendorong perubahan pola hunian baru yang mempertimbangkan kebutuhan masing-masing penghuni. Penggunaan metode pendekatan multidisiplin dengan menggabungkan teori psikologi manusia dengan teori desain arsitektural mampu memberikan solusi dalam membentuk pola hunian baru. Teori Maslow tentang kebutuhan manusia dan teori Ray Oldenburg tentang Three Realms of Space menjadi dasar teori dalam merancang. Hasil rancangan berupa desain modul unit hunian yang memiliki karakteristik ketiga tempat oleh Ray Oldenburg dan memenuhi teori piramida kebutuhan Maslow.

Investigation on Thermal Resistance and Capacitance Characteristics of a Highly Integrated Power Control Unit Module

With the increasing integration density of power control unit (PCU) modules, more functional power converter units are integrated into a single module for applications in electric vehicles or hybrid electric vehicles (EVs/HEVs). Different types of power dies with different footprints are usually placed closely together. Due to the constraints from the placement of power dies and liquid cooling schemes, heat-flow paths from the junction to coolant are possibly inconsistent for power dies, resulting in different thermal resistance and capacitance (RC) characteristics of power dies. This presents a critical challenge for optimal liquid cooling at a low cost. In this paper, a highly integrated PCU module is developed for application in EVs/HEVs. The underlying mechanism of the inconsistent RC characteristics of power dies for the developed PCU module is revealed by experiments and simulations. It is found that the matching placement design of power dies with a heat sink structure and liquid cooler, as well as a liquid cooling scheme, can alleviate the inconsistent RC characteristics of power dies in highly integrated PCU modules. The findings in this paper provide valuable guidance for the design of highly integrated PCU modules.

Question Selection in Template-Based Test Paper Models

The success of any educational program depends on its evaluation system. Examinations are a part of learning process which acts as an element in evaluation. For the smooth conduct of examinations of various universities and academic institutions, the test paper generation process would be helpful. However, examination test paper composition is a multi-constraint concurrent optimization problem. Question selection plays a key role in test paper generation systems. Also, it is the most significant and time-consuming activity. The question selection is handled in traditional test paper generation systems by using a specified test paper format containing a listing of weightages to be allotted to each unit/module of the syllabus.

Efficiency of Working Fluids for Rankine Cycle in Energy-Saving Gas Transport Systems

In this paper, the application of various non-ozone-depleting low-boiling working fluids for the Rankine cycle is analyzed based on exergy efficiency. The Rankine cycle is used for high-efficiency waste heat recovery from flue gases generated in gas transport systems at natural gas compressor stations. The system was modelled based on calculations using the CHEMCAD software in conjunction with the “Energy unit” module compatible with the main program interface, which was used for assessing system energy efficiency. It was concluded that the neopentane Rankine cycle with a regenerator is more efficient. Preliminary economic analysis has shown that the proposed system has an acceptable payback period (up to 6 years).