scholarly journals Iterative Spatial Crowdsourcing in Peer-to-Peer Opportunistic Networks

Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1085
Author(s):  
Jurairat Phuttharak ◽  
Seng W. Loke

Spatial crowdsourcing is a potentially powerful method for incorporating human wisdom into mobile computations to solve problems while exploiting the advantages of mobility and context-awareness. This paper proposes and investigates task assignments and recruitment in iterative spatial crowdsourcing processes to find regions of particular interest among a collection of regions. We consider cases where associations between regions can be exploited to reduce costs and increase efficiency in crowdsourcing. We describe five approaches, incorporated into crowdsourcing algorithms, for reducing the cost (the number of queries required) and increasing the efficiency (reducing the number of rounds of querying required) in using such spatial crowdsourcing. We demonstrate the performance improvements gained using these approaches based on simulation scenarios. The findings show the interplay and relationships among our proposed approaches using a range of metrics including responses, energy consumption, costs, and time usage. These metrics are demonstrated via a range of scenarios, showing that our proposed approaches can lead to improved performance over randomly choosing regions for inquiry.

Mathematics ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1837
Author(s):  
YoungBeom Kim ◽  
Hyeokdong Kwon ◽  
SangWoo An ◽  
Hwajeong Seo ◽  
Seog Chung Seo

As the development of Internet of Things (IoT), the data exchanged through the network has significantly increased. To secure the sensitive data with user’s personal information, it is necessary to encrypt the transmitted data. Since resource-constrained wireless devices are typically used for IoT services, it is required to optimize the performance of cryptographic algorithms which are computation-intensive tasks. In this paper, we present efficient implementations of ARX-based Korean Block Ciphers (HIGHT and LEA) with CounTeR (CTR) mode of operation, and CTR_DRBG, one of the most widely used DRBGs (Deterministic Random Bit Generators), on 8-bit AVR Microcontrollers (MCUs). Since 8-bit AVR MCUs are widely used for various types of IoT devices, we select it as the target platform in this paper. We present an efficient implementation of HIGHT and LEA by making full use of the property of CTR mode, where the nonce value is fixed, and only the counter value changes during the encryption. On our implementation, the cost of additional function calls occurred by the generation of look-up table can be reduced. With respect to CTR_DRBG, we identified several parts that do not need to be computed. Thus, precomputing those parts in offline and using them online can result in performance improvements for CTR_DRBG. Furthermore, we applied several optimization techniques by making full use of target devices’ characteristics with AVR assembly codes on 8-bit AVR MCUs. Our proposed table generation way can reduce the cost for building a precomputation table by around 6.7% and 9.1% in the case of LEA and HIGHT, respectively. Proposed implementations of LEA and HIGHT with CTR mode on 8-bit AVR MCUs provide 6.3% and 3.8% of improved performance, compared with the previous best results, respectively. Our implementations are the fastest compared to previous LEA and HIGHT implementations on 8-bit AVR MCUs. In addition, the proposed CTR_DRBG implementations on AVR provide better performance by 37.2% and 8.7% when the underlying block cipher is LEA and HIGHT, respectively.


2011 ◽  
Vol 480-481 ◽  
pp. 1197-1200
Author(s):  
Feng Liu ◽  
Jun Min Wang

In recent years, in order to reduce building energy consumption in China, and vigorously promote the development of ecological construction, the paper studies disadvantages of the cost of traditional project management applications in the ecological construction projects, exploring specific cost management adapt to the ecological construction project.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Zhangjie Fu ◽  
Jingnan Yu ◽  
Guowu Xie ◽  
Yiming Chen ◽  
Yuanhang Mao

With the rapid development of the network and the informatization of society, how to improve the accuracy of information is an urgent problem to be solved. The existing method is to use an intelligent robot to carry sensors to collect data and transmit the data to the server in real time. Many intelligent robots have emerged in life; the UAV (unmanned aerial vehicle) is one of them. With the popularization of UAV applications, the security of UAV has also been exposed. In addition to some human factors, there is a major factor in the UAV’s endurance. UAVs will face a problem of short battery life when performing flying missions. In order to solve this problem, the existing method is to plan the path of UAV flight. In order to find the optimal path for a UAV flight, we propose three cost functions: path security cost, length cost, and smoothness cost. The path security cost is used to determine whether the path is feasible; the length cost and smoothness cost of the path directly affect the cost of the energy consumption of the UAV flight. We proposed a heuristic evolutionary algorithm that designed several evolutionary operations: substitution operations, crossover operations, mutation operations, length operations, and smoothness operations. Through these operations to enhance our build path effect. Under the analysis of experimental results, we proved that our solution is feasible.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Bin Zhou ◽  
ShuDao Zhang ◽  
Ying Zhang ◽  
JiaHao Tan

In order to achieve energy saving and reduce the total cost of ownership, green storage has become the first priority for data center. Detecting and deleting the redundant data are the key factors to the reduction of the energy consumption of CPU, while high performance stable chunking strategy provides the groundwork for detecting redundant data. The existing chunking algorithm greatly reduces the system performance when confronted with big data and it wastes a lot of energy. Factors affecting the chunking performance are analyzed and discussed in the paper and a new fingerprint signature calculation is implemented. Furthermore, a Bit String Content Aware Chunking Strategy (BCCS) is put forward. This strategy reduces the cost of signature computation in chunking process to improve the system performance and cuts down the energy consumption of the cloud storage data center. On the basis of relevant test scenarios and test data of this paper, the advantages of the chunking strategy are verified.


Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8058
Author(s):  
Christian E. Galarza ◽  
Jonathan M. Palma ◽  
Cecilia F. Morais ◽  
Jaime Utria ◽  
Leonardo P. Carvalho ◽  
...  

This paper proposes a new theoretical stochastic model based on an abstraction of the opportunistic model for opportunistic networks. The model is capable of systematically computing the network parameters, such as the number of possible routes, the probability of successful transmission, the expected number of broadcast transmissions, and the expected number of receptions. The usual theoretical stochastic model explored in the methodologies available in the literature is based on Markov chains, and the main novelty of this paper is the employment of a percolation stochastic model, whose main benefit is to obtain the network parameters directly. Additionally, the proposed approach is capable to deal with values of probability specified by bounded intervals or by a density function. The model is validated via Monte Carlo simulations, and a computational toolbox (R-packet) is provided to make the reproduction of the results presented in the paper easier. The technique is illustrated through a numerical example where the proposed model is applied to compute the energy consumption when transmitting a packet via an opportunistic network.


2020 ◽  
Author(s):  
Moira Pryhoda ◽  
Rachel Wathen ◽  
Jay Dicharry ◽  
Kevin Shelburne ◽  
Bradley Davidson

The objective of this research was to determine if three alternative shoe upper closures improve biomechanical performance measures relative to a standard lace closure in court-based movements. NCAA Division 1 and club-level male athletes recruited from lacrosse, soccer, tennis, and rugby performed four court-based movements: Lateral Skater Jump repeats (LSJ), Countermovement Jump repeats (CMJ), Triangle Drop Step drill (TDS), and Anterior-Posterior drill (AP). Each athlete performed the movements in four shoe upper closures: Standard Closure, Lace Replacement, Y Wrap, and Tri Strap. Ground contact time, peak eccentric rate of force development (RFD), peak concentric GRF, peak concentric COM power, eccentric work, concentric work, and movement completion time were measured. Tri Strap saw improvements in four of seven biomechanical variables during CMJ and LSJ and one variable during TDS. Lace Replacement delivered improvements in one performance measure during CMJ, LSJ, and AP, and two variables in TDS. Y Wrap improved performance in three performance measures during LSJ and impaired performance in two measures during CMJ and three measures during AP. Tri Strap provided the most consistent performance improvements across all movements. This study allowed for the mechanical properties of the shoe lower to remain consistent across designs to examine if an alternative shoe upper closure could enhance performance. Our results indicate that increased proprioception and/or mechanical properties due to the alternative closures, especially Tri Strap, improves athlete performance, which concludes that the design of the shoe upper is an essential consideration in shoe design.


2020 ◽  
Author(s):  
Felipe Przysiada† ◽  
Diego Merks ◽  
Eduardo Silva ◽  
Alessandro Brawerman

The cost of electricity in Brazilian homes is increasingly high. This project consists of bringing a complete and easily accessible solution aiming to benefit the economy, in a much broader way, both for the end user and for the electricity generating system, which today has difficulty in meeting demand, as well as it provides a reduction in the environmental impact caused by the constant expansion of hydroelectric plants and other sources of energy. The use of this system, the Electricity Consumption Monitoring System, allows the user to have control of each equipment installed in the premises. The equipment in monitored by a device designed and built in this project. From these monitoring devices, which perform periodic measurements, it is possible to make a daily, weekly or monthly survey of the consumption of each equipment in the residence, sending alert messages, for excessive energy consumption, thus defining a user profile and even creating limitations for monthly spending. With this, the user will have the necessary resources to manage their energy consumption over the days, without having surprises at the end of the month.


2021 ◽  
Author(s):  
BASIL OLUFEMI AKINNULI ◽  
OLADELE AWOPETU ◽  
OLUWASEUN OLUWAGBEMIGA OJO

Abstract The crankshaft and engine block of automobile wear or fail after certain years of usage. The cause of failure is a contributing factor to the power loss of the engine. Power loss reduces the performance of the vehicle. Due to the economic situation in Nigeria, the cost of buying new engines is usually high and some used engines have problems that are latent. Pre-test engine analysis was carried out and torque of each selected engine was measured with a dynamometer to know the speed of the worn engine. Disassembly of four (4) cylinder engines namely; Toyota, Nissan, Mitsubishi, and Mazda were carried out and the affected failed parts, namely; main bearing, crankpin journal, and bore cylinder diameter were determined and the level of their wear as well as power losses ascertained using measuring instruments. For easy computation and analysis, a computer software using C-sharp programming language was developed to determine the power loss and predicting machining level of refurbish-ability and tested for performance evaluation. The model and its developed software are decision support tools for any automotive industry where maintenance and management of engines for improved performance and efficiency of operation is the focus.


Author(s):  
Yann Staelens ◽  
F. Saeed ◽  
I. Paraschivoiu

The paper presents three modifications for an improved performance in terms of increased power output of a straight-bladed VAWT by varying its pitch. Modification I examines the performance of a VAWT when the local angle of attack is kept just below the stall value throughout its rotation cycle. Although this modification results in a very significant increase in the power output for higher wind speeds, it requires abrupt changes in the local angle of attack making it physically and mechanically impossible to realize. Modification II improves upon the first by replacing the local angle of attack by the blade static-stall angle only when the former exceeds the latter. This step eliminates the two jumps in the local effective angle of attack curve but at the cost of a slight decrease in the power output. Moreover, it requires a discontinuous angle of attack correction function which may still be practically difficult to implement and also result in an early fatigue. Modification III overcomes the limitation of the second by ensuring a continuous variation in the local angle of attack correction during the rotation cycle through the use of a sinusoidal function. Although the power output obtained by using this modification is less than the two preceding ones, it has the inherent advantage of being practically feasible.


2001 ◽  
Vol 13 (03) ◽  
pp. 109-115 ◽  
Author(s):  
SHIH-CHING LIN ◽  
CHING-HSING LUO ◽  
TSU-FUH YEH

An indirect calorimetry system of measuring oxygen consumption and carbon dioxide production has been frequently used for preterm infants. The energy consumption and metabolic measurements are based on flow-through technology. The noninvasive measurement feature of the indirect calorimeter is widely used in pediatric clinical research. However, the indirect calorimeter has several limitations for small preterm infants, particularly the ill infant weighing < 1.0 kg. In this paper, we propose some technologies and methodologies to improve the performance of the indirect calorimetry. According to these technologies and methodologies, we redesign the indirect calorimeter proposed in our pervious study. The laboratory evaluation at the different alcohol combustion rates and several exhaust flow rates is used to survey the improved performance. As the results, the accuracy and precision is enhanced by these methods and the lowest oxygen consumption rate, 4.35 ml/min, fits for baby weight of 0.66 kg. It is demonstrated that the performances of new indirect calorimetry are substantially improved. It can be applied to calculate the energy consumption and metabolic rate for low-birth-weight infants in clinical research.


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