Non-real Time Research Articles

Program associated 3D non-real-time service on terrestrial DTV

One of the unresolved problems in providing viable stereoscopic 3D video services based on terrestrial DTV is to carry additional video while maintaining existing 2D video quality within limited bandwidth. Mitigating this problem, our proposed 3D service incorporates ATSC Non- Real-Time (NRT) transmission scheme in which the additional video stream delivered in advance of use and stored for later consumption. At later time when transmitting an air AV program associating the additional video previously sent, a receiving device is able to play stereoscopic 3D video by combining real-time video and the stored additional video synchronously. In this paper, we propose backward compatible system for the 3D NRT service and show that our implementation successfully presents the new stereoscopic 3D video service based on Terrestrial DTV.

DMB 파일캐스팅 서비스 기술

DMB provides various kinds of data services such as BWS and TPEG service in addition to audio and video services. But recently the necessity of new business models creating profit has been on the rise due to the saturation of DMB receiver market and break-down of market barrier between mobile IPTV and DMB services. This paper introduces DMB filecasting service technology, which can be expected a new profit-creative business model. The purpose of DMB filecasting service is to transmit non-real time multimedia contents based on DMB AF format to the users through DMB channels. It makes possible to consume DMB contents with any DMB-installed device anytime, anywhere and share them with others. Also DMB filecasting service makes consumption and request of DMB contents possible to be extented to a variety of networks as well as DMB channels. The paper explains the standardization status of DMB filecasting service and various DMB filecasting service scenarios. And also it proposes a signalling methode, a transmission and reception protocol and a receiver structure using DMB broadcasting program guide information.

Combined Queue Management and Scheduling Mechanism to Improve Intra-User Multi-Flow QoS in a Beyond 3,5G Network

Packet scheduling and buffer management are the two important functions adopted in networks design to ensure the Quality of Service (QoS) when different types of packets with different needs of quality share the same network resources. The Packet scheduling policy determines packet service priorities at the output link, it can reduce packet delay and delay jitter for high-priority traffic. The buffer management involves packet dropping and buffer allocation. The overall goal of such schemes proposed in High Speed Downlink Packet Access (HSDPA) is to take advantage of the channel variations between users and preferably schedule transmissions to a user when the channel conditions are advantageous; it does not take in consideration the characteristics of the flows composing the transmitted traffic to the user. This paper compares two queue management mechanisms with thresholds applied for packets transmitted to an end user in HSDPA network. Those mechanisms are used to manage access packets in the queue giving priority to the Real Time (RT) packets and avoiding the Non Real Time (NRT) packets loss. The authors show that the performance parameters of RT packets are similar in the two mechanisms, where as the second mechanism improves the performance parameters of the NRT packets.

A Survey on Energy-Efficient Routing Techniques with QoS Assurances for Wireless Multimedia Sensor Networks

The recent technological advances in micro electro-mechanical systems have promoted the development of a powerful class of sensor-based distributed intelligent systems capable of ubiquitously retrieving multimedia information, namely Wireless Multimedia Sensor Networks (WMSNs). WMSNs are gaining more popularity day by day as they are envisioned to support a large number of both non-real time and real-time multimedia applications. However, satisfying the stringent quality of service (QoS) requirements of multimedia transmission in a resource-constrained sensor network environment places new challenges to routing. As an outcome, optimal energy and application-specific QoS aware routing for WMSNs has gained considerable research attention recently. In this paper, current state-of-the-art in energy-efficient routing techniques for WMSNs is surveyed together with the highlights of the performance issues of each strategy. We outline the design challenges of routing protocols for WMSNs followed by the limitations of current techniques designed for non-multimedia data transmission. Further, a classification of recent routing protocols for WMSNs and a discussion of possible future research trends are presented.

Utility Based Scheduling and Call Admission Control for LTE (3GPP) Networks

In this paper, we propose to design a call admission control algorithm which schedules the channels for real time and non-real time users based on Utility function. In Long Term Evolution (LTE) 3GPP Networks, several works were done on call admission control but these works rarely considers scheduling of resources to the real time and non-real time users. The call requests are classified into new call (NC) request and handoff call (HC) request and the type of services are classified as VoIP and video. Then based upon the received signal strength (RSS) value, the channel is estimated as good channel or bad channel. Resource allocation is made for VoIP users based on traffic density. Then non-VoIP users and the non-real time users are allocated resource blocks using the channel condition based marginal utility function. When there are no sufficient resources to allocate, it allocates the resources of bad channel users there by degrading their service. Thus from our simulation results we show that this admission control algorithm provides channel quality and prioritizes the handover calls over new calls which allocates resources to all kinds of users.

A QoS guaranteeing MAC layer protocol for the "underdog" traffic

With the tremendous boom in the wireless local area network arena, there has been a phenomenal spike in the web traffic which has been triggered by the growing popularity of real-time multimedia applications. Towards this end, the IEEE 802.11e medium access control (MAC) standard specifies a set of quality-of-service (QoS) enhancement features to ensure QoS for these delay sensitive multimedia applications. Most of these features are unfair and inefficient from the perspective of low priority (non-real time) traffic flows as they tend to starve the non-real time flows depriving them of appropriate channel access, hence throughput. To that extent, this article proposes a MAC protocol that ensures fairness in the overall network performance by still providing QoS for real-time traffic without starving the "underdog" or non-real-time flows. The article first presents analytical expressions supported by Matlab simulation results which highlight the performance drawbacks of biased protocols such as 802.11e. It then evaluates the efficiency of the proposed "fair MAC protocol" through extensive simulations conducted on the QualNet simulation platform. The simulation results validate the fairness aspect of the proposed scheme.

Analysis and Performance Evaluation of IEEE 802.11 WLAN

With fast deployment of wireless local area networks VoIP over IEEE 802.11 wireless local area network (WLAN) is growing very fast and is providing a cost effective alternative for voice communications. WLANs were initially set up to handle bursty nonreal time type of data traffic. Therefore, the wireless access protocols initially defined are not suitable for voice traffic. Subsequently, updates in the standard have been made to provision for QoS requirements of data, especially the real time traffic of the type voice and video. Despite these updates, however, transmitting voice traffic over WLAN does not utilize the available bandwidth (BW) efficiently, and the number of simultaneous calls supported in practice is significantly lower than what the BW figures would suggest. Several modifications have been proposed to improve the call capacity, and recently isochronous coordination function (ICF) was introduced to mitigate the problem of low call capacity. The proposed modified ICF which further improves the performance in terms of the call capacity. The proposed scheme uses multiplexing and multicasting in the downlink to substantially increase the call capacity.

Multibeam satellite frequency/time duality study and capacity optimization

In this paper, we investigate two new candidate transmission schemes, non-orthogonal frequency reuse (NOFR) and beam- hopping (BH). They operate in different domains (frequency and time/space, respectively), and we want to know which domain shows overall best performance. We propose a novel formulation of the signal-to-interference plus noise ratio (SINR) which allows us to prove the frequency/time duality of these schemes. Further, we propose two novel capacity optimization approaches assuming per-beam SINR constraints in order to use the satellite resources (e.g., power and bandwidth) more efficiently. Moreover, we develop a general methodology to include technological constraints due to realistic implementations, and obtain the main factors that prevent the two technologies dual of each other in practice, and formulate the technological gap between them. The Shannon capacity (upper bound) and current state-of-the-art coding and modulations are analyzed in order to quantify the gap and to evaluate the performance of the two candidate schemes. Simulation results show significant improvements in terms of power gain, spectral efficiency and traffic matching ratio when comparing with conventional systems, which are designed based on uniform bandwidth and power allocation. The results also show that BH system turns out to show a less complex design and performs better than NOFR system specially for non-real time services.

RFID와 BIM을 활용한 건설 자재 물류 및 진도관리 시뮬레이터 개발

건설 프로젝트의 효과적인 물류 및 진도관리를 위하여 다양한 연구 및 시도가 이루어지고 있다. 이중 RFID+4D 기술은 철골, PC, 커튼월과 같은 공장 주문형 자재의 공급망 및 진도관리를 위해 개발된 기술로써 공기 및 비용 절감에 대한 효과가 있는 시스템으로 보고된 바 있다. 하지만 기존의 시스템은 그 효과에 비해 모델링 비용, 실시간 정보 반영의 난이, 시스템 운영을 위한 추가 인력 배치 등의 문제로 인해 시스템 확산이 미비한 상태에 있다. 따라서 본 연구에서는 이러한 기존 RFID+4D 프로세스의 문제를 해결하기 위한 체계 및 제안된 체계를 활용한 웹 기반의 실시간 4D 시뮬레이터를 개발하였다. 본 연구에서 개발된 체계 및 시스템은 기존 RFID+4D 프로세스 운영의 비용 및 정보 활용성을 향상시킴으로써 기술 확산에 기여할 것으로 기대되며 특히 최근 이슈화되고 있는 BIM 정보와의 연계를 통해 설계 단계에서 생성된 BIM을 시공 단계에서 활용하기 위한 방법으로 활용 가능할 것으로 판단된다. There have been research and developments for effective and efficient logistics and progress management in a construction project. Among them, RFID+4D has been developed for the supply chain management of long-lead item materials such as steel component, precast concrete component and curtain wall by integrating RFID with 4D CAD. And the feasibility of RFID+4D has been verified and validated and the benefits in terms of time and cost were shown in several case studies. However, the previous development of RFID+4D has not been adapted widely because of additional modeling cost, non-real time data update, additional labor for data update, and so forth. Therefore, this research has proposed a framework and process for solving these problems. And the web based simulation system has been developed and verified based on the proposed framework. The proposed framework and process can improve the existing RFID+4D system in a construction project by saving its operation cost and utilizing project information more efficiently and effectively. Also it is expected that the proposed framework could be applied to a method transferring design RIM data to construction BIM data.

Electroplating production scheduling by cyclogram unfolding in dynamic hoist scheduling problem

This article presents a scheduling problem that exists in electroplating lines. An electroplating line is an automated manufacturing system which covers machine parts with a coat of metal. It consists of a set of tanks that chemically process the items and hoists that transport the items between workstations. Scheduling the movements of these hoists is commonly called a hoist scheduling problem. The most common approaches to the problem are cyclic hoist scheduling problem and dynamic hoist scheduling problem (DHSP). This article presents a DHSP solution method. The method divides the problem into real time and non-real time. Special schedules, called cyclograms, allow minimisation of the length of non-real time calculations. A notion of the problem is introduced, an outline of a scheduling system is presented, as well as the heuristic algorithm itself. The results of the described method, referred to as a cyclogram unfolding method, are compared to several cases available in the literature.

An energy-efficient delay reduction technique for supporting WLAN-based VoIP in SmartPhone

For non-real time data such as Web or e-mail, the 802.11 PSM scheme can be a useful mechanism for reducing power consumption effectively. However, there are some limitations when these are used for voice communication in which the main traffic is composed of delay-sensitive data like voice or call signaling. In this paper, in order to overcome the limitations, we present an efficient power saving scheme which can minimize power consumption while guaranteeing the delay constraint during call signaling and talk time. Furthermore, in order to illustrate the aims of the proposed approach, the terminal systems are implemented and evaluated by measuring average call connection delay and power consumption. The experimental results show that our approach can minimize traffic delay and power consumption, and find an optimal sleep threshold value according to network condition changes.

Transforming enterprise communications through the blending of social networking and unified communications

The blending of the emerging technology of social networking with unified communications has the potential to radically change how enterprise employees communicate. Enterprise social networking applications help employees build organizational collective wisdom and work more effectively by discovering implied relationships through shared social data. Unified communications applications provide suites of real time and non-real time communication enablers like click-to-call, click-to-IM, presence, and voice mail. Blending these two technologies permits text/audio/video conversations to be treated as social objects whose data and metadata can be stored, searched, tagged, and followed in social networking applications, just like other social objects such as people. In turn, exposing social data about conversations enables innovative new capabilities like recommending conversations for someone to participate in based on inferred interests, or finding and contacting an expert based on knowledge about conversations in the social network. This paper describes People & Projects, an experimental application used in Alcatel-Lucent to investigate advances in enterprise social networking. It also outlines early work on the integration of social networking and unified communications.

QoS Provisioning for Heterogeneous Services in Cooperative Cognitive Radio Networks

In this paper, we propose a spectrum allocation framework that jointly considers the Quality-of-Service (QoS) provisioning for heterogeneous secondary Real-Time (RT) and Non-Real Time (NRT) users, the spectrum sensing, spectrum access decision, channel allocation, and call admission control in distributed cooperative Cognitive Radio Networks (CRNs). Giving priority to the RT users with QoS requirements in terms of the dropping and blocking probabilities, a number of the identified available channels are allocated to the optimum number of the RT users that can be admitted into the network, while the remaining identified available channels are allocated adaptively to the optimum number of the NRT users considering the spectrum sensing and utilization indispensability. Extensive analytical and simulation results are provided to demonstrate the effectiveness of the proposed QoS-based spectrum resource allocation framework.

Adaptive resource allocation for multi-user multi-server power-line communication OFDM systems

The bits and power allocation model of adaptive power-rate mixture for multi-user multi-server power-line communication systems was analyzed with the restrictions of maximal total power, fixed rate for each real time (RT) user, minimal rate for each non-real time (NRT) user, maximal bits and power for each subcarrier in each orthogonal frequency division multiplexing (OFDM) symbol. An algorithm of resource dynamic allocation in the first OFDM symbol of each frame and resource optimal adjustment in the latter OFDM symbol of each frame was proposed. In the first OFDM symbol of every frame, resource is firstly assigned for RT users so as to minimize their total used power until satisfying their fixed rates; secondly the remainder resource of power and subcarriers are assigned for NRT users so as to minimize their total used power until satisfying their minimal rates also; lastly the remainder resource is again assigned for NRT users according to the proportional fairness strategy so as to maximize their total assigning rate. In the latter OFDM symbol of each frame, bits are swapped and power is adjusted for every user based on the resource allocation results of anterior OFDM symbol. The algorithm is tested in the typical power-line channel scenarios and the simulation results indicate that the proposed algorithm has better performances than the classical multi-user resource allocation algorithms and it realizes the multiple aims of multi-user multi-server resource allocation for power-line communication systems.

전환제어법칙 설계 및 검증에 관한 연구

The flight control law designed for prototype aircraft often leads to degraded stability and performance, although developed control law verify by non-real time simulation and pilot based evaluations. Therefore, the proper evaluation methods should be applied such that flight control law designed can be verified in real flight environment. The one proposed in this paper is IFS (In-Flight Simulator). Currently, this system has been implemented into the F-18 HARV (High Angle of Attack Research Vehicle), SU-27 and F-16 VISTA (Variable stability In flight Simulation Test Aircraft) programs. The IFS necessary switching control law such as fader logic and integrator stand-by mode to reduce abrupt transient and minimize the integrator effect for each flight control laws switching. This paper addresses the concept of switching mechanism with fader logic of TFS (Transient Free Switch) and stand-by mode of feedback type based on SSWM (Software Switching Mechanism). And the result of real-time pilot evaluation reveals that the aircraft is stable for inter-conversion of flight control laws and transient response is minimized.

Aşk Mesnevilerinde Şimdiki Zaman Algısı

Time, when looked at in the limits of esthetics, is a matter that needs the help of philosophy. Every behavior belongs to time, is a point that affects all determinants about the text. Time has been the most important fact of religion with the creating action of God. Besides, in divan poetry and especially in mesnevis time is used in different ways. The relationship of time with reality, used with the event, place, and personality, is in different dimensions. Because of that, every mention about time, makes us to mention about reality at the same time. So, time in mesnevis is used sometimes above the objective perception, and is sometimes far away from reality. Generally poets trend to the emphasis of non-real time by leaving the objective time in their mesnevis. The heroes limited in the time period of the present time or the“ moment” go to different dimensions in time, so move away from the real time, that’s reality. When the emphasis to the present tense perception can be observed more in love mesnevi “Husn u Ashk” , we wanted to compare the other love mesnevis by taking “Yusuf u Zulayha” and “Layla and Macnun”. So we trend to these texts to get ideas about the changes of reality perception. Our goal is not only to get the statistical results of words belongs to time, is to understand that present tense perception causes to verbs or verbs add to qualities to time.

Methods for Analysis of Multiservice Wireless Cellular Communication Networks with Queues of Nonreal Time Calls. Part II. Guard Channels Strategy

Methods for Analysis of Multiservice Wireless Cellular Communication Networks with Queues of Nonreal Time Calls. Part II. Guard Channels Strategy

Performance analysis of the CAC scheme CARETON under mixed cell environment in overlay networks

The paper proposes a call admission control (CAC) scheme to offer best services to the users in the next generation heterogeneous networks. It optimises the available resources without compromising the interest of the service providers. It has combined the three commonly used CAC schemes – guard channel, buffer-based and priority-based schemes. It considers wireless overlay model for analysing the heterogeneity with detailed analysis of the WLAN-cellular mixed cell environment. The scheme considers differentiated services for the real time and non-real time calls to provide appropriate quality of service (QoS). The proposed scheme has been evaluated through simulation. The results show that the scheme outperforms some significant CAC schemes and shows even better performance under cellular-WLAN mixed environment due to the dual subscription of the users with dual mobile terminal.

Methods for Analysis of Multiservice Wireless Cellular Communication Networks with Queues of Nonreal Time Calls. Part I. Cut off Strategy

Methods for Analysis of Multiservice Wireless Cellular Communication Networks with Queues of Nonreal Time Calls. Part I. Cut off Strategy

Development and Implementation of Control Algorithms for Synchronous Generator

This paper proposes a DSP based simulator for development and implementation of control algorithms. The simulator is used to control a synchronous aggregate model in real time. The simulator consists of a PC (on which a synchronous generator connected to AC network is simulated) connected through a communication channel to a DSP (on which the control algorithm is implemented). The simulator makes implementation of a control algorithm faster and easier. It also enables verification of a control algorithm in real time. Simulation results show that there are no significant differences between non-real time simulations (on a PC) and real time simulations (on a DSP based simulator). This paper also presents design and implementation of a nonlinear control algorithm for excitation control system based on the Lyapunov's direct method. Both conventional excitation control algorithm and proposed nonlinear excitation control algorithm were implemented and tested on the real time simulator. The obtained simulation results show that proposed nonlinear excitation control algorithm better damps electromechanical oscillations than conventional excitation control algorithm.