Joint Interference Alignment and Bi-Directional Scheduling for MIMO Two-Way Multi-Link Networks

By means of the emerging technique of dynamic Time Division Duplex (TDD), the switching point between uplink and downlink transmissions can be optimized across a multi-cell system in order to reduce the impact of inter-cell interference. It has been recently recognized that optimizing also the order in which uplink and downlink transmissions, or more generally the two directions of a two-way link, are scheduled can lead to significant benefits in terms of interference reduction. In this work, the optimization of bi-directional scheduling is investigated in conjunction with the design of linear precoding and equalization for a general multi-link MIMO two-way system. A simple algorithm is proposed that performs the joint optimization of the ordering of the transmissions in the two directions of the two-way links and of the linear transceivers, with the aim of minimizing the interference leakage power. Numerical results demonstrate the effectiveness of the proposed strategy.Comment: To be presented at ICC 2015, 6 pages, 7 figure

Selecting the optimal renewable energy using multi criteria decision making

Renewable energies are well-known as one of the most important energy resources not only due to limited other energy resources, but also due to environmental problems associated with air pollutants and greenhouse gas emissions. Renewable energy project selection is a multi actors and sophisticated problem because it is a need to incorporate social, economic, technological, and environmental considerations. Multi criteria decision making (MCDM) methods are powerful tools to evaluate and rank the alternatives among a pool of alternatives and select the best one. COPRAS (COmplex PRoportional ASsessment) is an MCDM technique which determines the best alternative by calculating the ratio to the ideal solution and the negative ideal solution. On the other hand, analytical hierarchy process (AHP) is widely used in order to calculate the importance weights of evaluation criteria. In this paper an integrated COPRAS-AHP methodology is proposed to select the best renewable energy project. In order to validate the output of the proposed model, the model is compared with five MCDM tools. The results of this paper demonstrate the capability and effectiveness of the proposed model in selecting the most appropriate renewable energy option among the existing alternatives. First published online: 23 Sep 201

A new hybrid model for evaluating the working strategies: case study of construction company

Selection of the working strategy is a critical problem and it plays a significant role in the success of organization development. On the other hand, selecting the most appropriate working strategy among a pool of alternatives is a multi-criteria decision making (MCDM) problem. Since every working strategy has its benefits and costs and may bring a company different opportunities and risks, which kind of working strategy is the most appropriate for a company to accomplish is a sophisticated and complex decision with a high degree of uncertainty. Therefore, the current paper proposed an integrated evaluation model based on the analytic network process (ANP) and the complex proportional assessment (COPRAS), to help the decision makers or managers with the selection of proper working strategy in a fuzzy environment where the fuzziness and uncertainties are handled with linguistic terms parameterized by triangular fuzzy numbers (TFNs). In this paper fuzzy ANP (FANP) is utilized to take into account interdependence and dependencies and determine the importance weights of benefit, opportunities, cost and risk (BOCR) factors, and fuzzy COPRAS is applied to rank the alternatives. To show the potential application of the proposed model, a real world application is conducted to illustrate the use of the proposed model for the working strategy selection problem. The results show the capability and effectiveness of the proposed model

Authenticated key agreement mediated by a proxy re-encryptor for the Internet of Things

International audienceThe Internet of Things (IoT) is composed of a wide range of heterogeneous network devices that communicate with their users and the surrounding devices. The secure communications between these devices are still essential even with little or no previous knowledge about each other and regardless of their resource capabilities. This particular context requires appropriate security mechanisms which should be wellsuited for the heterogeneous nature of IoT devices, without pre-sharing a secret key for each secure connection. In this work, we first propose a novel symmetric cipher proxy re-encryption scheme. Such a primitive allows a user to delegate her decryption rights to another with the help of a semi-trusted proxy, but without giving this latter any information on the transmitted messages and the user's secret keys. We then propose AKAPR, an Authenticated Key Agreement mediated by a Proxy Re-encryptor for IoT. The mechanism permits any two highly resource-constrained devices to establish a secure communication with no prior trust relationship. AKAPR is built upon our proposed proxy re-encryption scheme. It has been proved by ProVerif to provide mutual authentication for participants while preserving the secrecy of the generated session key. In addition, the scheme benefits from the lightness of our proxy re-encryption algorithm as it requires no expensive cryptographic operations such as pairing or modular exponentiatio

Gathering Sensor Data in Home Networks with IPFIX

Abstract. New developments in military, health and home areas call for new approaches for data acquisition in real-time. Such application areas frequently include challenging requirements for collection, process-ing and analysis of environmental data. Wireless Sensor Networks can collect such environmental data efficiently. Collected sensor node data needs to be transmitted in an efficient way due to limitations of sensor node resources in battery power and available bandwidth. In this paper, we present a method for efficient transmission of sensor measurement data using the IETF standard IPFIX. We show that its template based design is suitable for efficient transmission of senor data with low band-width consumption. In this paper, we present the protocol and its imple-mentation in Wireless Sensor Networks (WSNs). Additionally, a header compression scheme is introduced which further reduces communication cost during data transmission.

Performance of Holstein calves fed whole milk with or without kefir

A growing body of evidence suggests health-promoting effects of kefir consumption on different nonruminant species, leading to the speculation that kefir may act as a probiotic and benefit calf performance and health. Our objectives were to determine effects of feeding kefir on performance and health of calves in the first 70 d of life. Thirty 3-d-old female Holstein calves (body weight = 38.2 ± 3.1 kg) were blocked by initial body weight and assigned randomly to 1 of 3 treatments (1 calf per pen; 10 pens per treatment). Kefir was added to whole milk (vol/vol) at 0:1 (control; KF0), 1:3 (KF1), or 1:1 (KF2) and fed twice per day (0800 and 1600 h) from d 3 through 45 and then once per day until weaning, which occurred on d 50. Pre- and postweaning intake of starter, daily body weight gain, and gain-to-feed ratio exhibited no difference among treatments. Adding kefir to whole milk fed directly to calves had no effect on concentration of blood metabolites collected on d 20, 40, and 70. Body length on d 50 (weaning) and 70 was greater in kefir-fed calves. Kefir intake improved fecal scores and reduced days with diarrhea during the first 2 wk of life. Apparent digestibility of organic matter, ether extract, crude protein, and neutral detergent fiber remained unaffected by treatment. Overall, it appears that directly feeding kefir to calves during the preweaning period did not improve the performance of calves under the conditions of the current study; however, its consumption marginally improved body length and fecal consistency in the first weeks of life, which is an important concern in intensive calf-rearing systems. Feeding kefir to neonatal calves may be a viable approach to improve the health of calves in commercial calf-rearing operations, although to validate its health-promoting effects additional research is needed to investigate its effects under different calf-rearing conditions

Numerical investigation of rigidity and flexibility parameters effect on superstructure foundation behavior using three-dimensional finite element method

A comprehensive three-dimensional finite element of the superstructure foundation model includes the effect of lots of important parameters on the structure performance. Among these parameters, rigidity and flexibility of raft foundations and soil interactions become an important aspect of design due to their efficient, practical and economic performance compared to the isolated foundation for buildings and heavy projects. In this study, the elastoplastic constitutive model based on the three-dimensional finite element (FE) method is employed to investigate rigidity and flexibility parameters' effect on superstructure foundation behavior. The model is developed and calibrated using SAFE 12 and ABAQUS programs by comparing two case studies. Utilizing the Winkler approach, flexible soil foundations are designed. In addition, technics like turning the raft into a boxed-raft or piled raft are evaluated to improve the performance of the raft from a rigidity and flexibility point of view. Then, the effects of various factors and conditions which affect design such as geometry, modulus of subgrade reaction, stiffness of the foundation, the effect of soil and thickness of foundation, piled raft foundations (PRF) and boxed raft foundations are studied. The results demonstrate that the superstructure components such as shear walls and basement walls can significantly affect the deflection, shear stress, and bending moment of the raft and its structural design subsequently. Also, shear walls, as structural parts which transmit an important part of vertical and lateral loads to the foundation, can play an important role in the rigidity of the raft. It is concluded that using PRF instead of the simple raft, results in a much rigid foundation with more bearing capacity and less differential deflection. The results of this study have the potential to be utilized in the design of advanced superstructure, in which rigidity and flexibility act as the basic elements