Service Classes Research Articles

CZM-based FE numerical study on pull-out performance of adhesive bonded-in-rod (BiR) joints for timber structures

Bonded-in-Rod (BiR) connections for timber structures are becoming rather popular solution, in place of other traditional fastening techniques. Besides, design rules and recommendations in support of safe and robust verification are still poor in existing standards. As such, the actual mechanical performance and load-bearing capacity – which is severely affected by a multitude of operational parameters – should be possibly addressed with the support of experimental investigations. In this paper, a Cohesive Zone Modelling (CZM) based, Finite Element (FE) numerical investigation is proposed for a total of 144 BiR joints characterized by various geometrical and mechanical properties, including grain orientation (α = 0° or 90°), adhesive type (polyurethane or epoxy glue), diameter (d = 10, 14, 20 mm) and anchorage length of rods (L = 60, 100, 200, 400 mm) is presented. Most importantly, the attention is also focused on the analysis of service class effects / moisture content (9, 18 or 27 %) on the actual residual capacity of the examined joints, which is of paramount importance for safe design applications in timber structures. Based on validation of input model properties to past experimental results, the sensitivity of basic mechanical performance indicators for the examined BiR samples is discussed in the paper.

Implementasi Perubahan Sistem Informasi Keuangan pada Kantor Imigrasi Kelas I Non TPI Karawang

Financial management in government agencies is very important as it has a "specific" concept of performance, namely responsibility, synergy, transparency and innovation. The financial information system is one of the tools used to record various information system transactions that affect the operation and management of business support activity. The financial management process in the work unit of the Class I, Non-TPI Immigration Office in Karawang can be considered less effective and efficient as it goes through multiple stages with different applications, which underlie changes in the use of financial information. This article is to explain the implementation of changes in the financial information system in the Immigration Service Class I No TPI Karawang The method of writing this article is to combine descriptive qualitative research methods with observations, use of survey techniques, analysis, interpretation of data. and triangle. The results obtained are (1) Changes in the application system in the work unit of the Immigration Office Class 1 Non TPI Karawang generally facilitate tasks and work for users. (2) Comparing time effectiveness is not very important, but using an application to be able to perform different types of financial operations can minimize the occurrence of errors or non-response on a PC during the recording work. (3) The effectiveness of the work summary occurs in the reconciliation phase, where with the latest system the E-Recon reconciliation process between the work units and the PCPN is automated (it is not necessary to use CDA (Computer Data Archive). ) of ABAS (Accrual Based Accounting System) in E-Commerce.econ). (4) The SAKTI application can replace the 6 previous applications used in the Karawang Class 1 Immigration Office. (5) Changes in the financial information system do not reduce the existing existing tasks and functions as financial documents.

Beyond 5G URLLC evolution: New service modes and practical considerations

Ultra-Reliable Low Latency Communications (URLLC) arose to serve Industrial IoT (IIoT) use cases within 5G. However, currently, it has inherent limitations in supporting future services. Therefore, in this article, based on state-of-the-art research and practical deployment experience, from two distinct test networks from Finland and South Korea, we introduce and advocate for three variants of critical Machine-Type Communications (MTC), namely, broadband, scalable and extreme URLLC. Moreover, we discuss use cases and key performance indicators and identify two critical technology enablers for each new service class. Finally, we bring practical considerations from the IIoT testbed and provide an outlook towards new research directions.

Class inequalities in access to social capital in the metropolitan area of Buenos Aires

this paper analyzes social class inequalities in access to social capital. Quantitative methodology was used with data from the PI-Clases “Reproduction and social mobility in family trajectories and life courses” survey, conducted in the Metropolitan Area of Buenos Aires in 2015 (n = 1065). Social capital measures where derived from the Position Generator (Lin, 2001) to identify the volume, status and range of the respondent’s networks. Results show that there are class inequalities in access to social capital in terms of the number of contacts, mean status of contacts, range of contact’s status and highest status of contacts. Also, the working class is more heterogeneous in its access to social capital, suggesting it has a sector that has network ties with people from the middle class and a sector with lower social capital. The observed trend is of gradational differences between class strata, with more marked inequalities between the service, intermediate and working class, but with fluid class boundaries without social segregation. Also, social capital is conditioned by intergenerational mobility trajectory, showing a trend of elasticity in the class composition of social relationships. The upwardly mobile can increase their access to social capital but don’t reach the same level as the intergenerationally stable, while the downwardly mobile retain some social capital from their class origins.

Between trust and mistrust: master-servant relationships in Urdu writings of the 1860s–early 1900s

ABSTRACT Based on texts dealing with life in North Indian Muslim households of the second half of the nineteenth century, covering genres such as didactic tales, letters, guidebooks, and an autobiographical narrative, this essay looks at the representation of master-servant relationships as presented in these texts from the perspective of the master/mistress. As this was a period of transformation when traditional aristocratic households were gradually replaced by the new middle class, this essay, through a close textual analysis, underscores the gap between the normative and actual behaviour of the employing class, underlining the changes that came about with respect to the service classes while it attempted to maintain or acquire respectability on reduced incomes.

Nature of slavery and servitude in Mughal India

ABSTRACT The nature of service and submission in Mughal India was starkly different from modern times. The rhetoric of complete submission to the person of the Emperor guided the social relations of all orders. A reflection of this must have been experienced at the level of the household service gentry. Important elements in this service class were chelas (freed male slaves), sahelis (freed slave-girls) and khwajasaras (eunuchs). All three sections had an ambiguous placement in the social order. The chelas and sahelis were in principle free but their social realities and the nature of their services were similar to that of slaves. Eunuchs, on the other hand, provided widely varied services, ranging from administrative duties to mere harem attendance. The conditions of all these groups depended largely on the interactions between them and their immediate masters. The paper explores the dynamics of the varying nature of social realities and mobility experienced by these different sections, locating them within class and gender contexts.

Integration of Multi-Class Service Paradigm With Generic Trust Mechanism for Innovation, Customization and Adaptability in MANETs

Trust-based mechanisms are widely used in wireless networks of different kinds for providing security against attack. Trust mechanism provides security from various attacks using both detective and preventive manner. This paper presents a quality service paradigm that can be integrated with any underlying trust mechanism. The paradigm includes different flags corresponding to different services incorporated in various routing packets. The paradigm provides flexible customization and adaptability as per the demand of communicating nodes for effective data transfer. Various quality service classes are designed to formulate route as per the requirement to minimize the routing overhead and balancing of load among nodes. This paradigm power is the trust mechanism with proactive action for detection of malicious nodes in the network. The proposed paradigm is incorporated in an established trust mechanism and compared with standard version of that trust mechanism for packet delivery ratio and routing overhead.

The Implementation of Unified Application Data Collection and Analysis in Tobacco Enterprise Platform Design

With the continuous deepening and development of tobacco manufacturing informatization construction, tobacco manufacturing enterprises have the characteristics of strong production capacity, high degree of production automation, and advanced enterprise-level management information system. In order to cooperate with the market and brand strategy of the tobacco industry, the State Tobacco Monopoly Administration has carried out serious strategic thinking on informatization and customized the overall plan and strategic goals. In recent years, China’s informatization construction has made great progress, and both industries and enterprises have felt various benefits from the application of information technology. In the deployment and development of mobile services, it is often local and municipal mobile companies that, in order to meet the different needs of the market, immediately carry out corresponding services, resulting in one service for each municipal subsidiary in the same province or one platform for a class of services. Situation is good for quickly meeting user needs at that time. The exchange and communication of enterprise personnel information are becoming more and more frequent, and the collection of enterprise information through mobile has become a new way of enterprise information collection. The work orders, process parameters, documents, notifications, and instructions generated by the planning layer are sent to the production control layer to respond, guide, and trigger the production site events. The ultimate goal of mobile data collection is to gather the collected data into the enterprise production data center, which plays an important role in mobile devices, mobile performance, mobile planning, mobile balancing, mobile prediction, and so on. Based on the unified mobile application data collection method, this paper analyzed and analyzed the design of application architecture in the tobacco enterprise platform and further described the business functions, security performance, and system characteristics of the platform.

Mechanical properties of wood adhesive bond lines tested in service classes according to Eurocode 5

Depending on the expected use of timber structures and wood-based panels jointed with adhesives, Eurocode/European standard defines various service classes for the design of buildings, where different moisture ranges might be expected. As a result, it can be assumed that the amount of moisture in the adherend has a significant impact on wood-adhesive bond lines. In-situ nanoindentation was used to investigate the influence of moisture on mechanical properties in service conditions for commonly used structural and non-structural wood adhesive systems (polyvinyl acetate adhesive PVAc, a flexible two-component melamine-urea-formaldehyde adhesive MUF, urea-formaldehyde adhesive intended for form pressing applications UF A, and particle board urea-formaldehyde adhesive UF B, and a phenol-resorcinol-formaldehyde adhesive PRF).The urea-formaldehyde adhesive intended for form pressing applications and PRF adhesives displayed better stability in elastic behaviour and very little change in creep behaviour at elevated relative humidities. The thermoplastic adhesive PVAc, particleboard urea-formaldehyde (UF A), and MUF adhesive systems with flexible thermoplastic components showed lower stability with increasing relative humidity levels above 66%. The two-component MUF adhesives showed increasing creep with increasing flexible second component at elevated relative humidities. The pre-polymerized adhesive PVAc turned out to be the most sensitive one to moisture.

Deep reinforcement learning based flexible preamble allocation for RAN slicing in 5G networks

One of the most difficult challenges in radio access network slicing occurs in the connection establishment phase where multiple devices use a common random access channel in order to gain access to the network. It is now very well known that random access channel congestion is a serious issue in case of sporadic arrival of machine-to-machine nodes and may result in a significant delay for all nodes. Hence, random access channel resources are also needed to be allocated to different services to enable random access network slicing. In the random access channel procedure, the nodes transmit a selected preamble from a predefined set of preambles. If multiple nodes transmit the same preamble at the same random access channel opportunity, a collision occurs at the eNodeB. To isolate the one service class from others during this phase, one approach is to allocate different preamble subsets to different service classes. This research proposes an adaptive preamble subset allocation method using deep reinforcement learning. The proposed method can distribute preambles to different service classes according to their priority providing virtual isolation for service classes. The results indicate that the proposed mechanism can quickly adapt the preamble allocation according to the changing traffic demands of service classes.

Robust planning of sorting operations in express delivery systems

Parcel logistics services play a vital and growing role in economies worldwide, with customers demanding faster delivery of nearly everything to their homes. To move larger volumes more cost effectively, express carriers use sort technologies to consolidate parcels that share similar geographic and service characteristics for reduced per-unit handling and transportation costs. This paper focuses on an operational planning problem that arises in two-stage sort systems operating within parcel transportation networks. In this context, primary sorters perform an initial grouping of parcels into “piles” that are subsequently dispatched when necessary to secondary sorters; there, each pile’s parcels are fine-sorted based on their final destinations and service class for packing into outbound transportation vehicles. Such systems must be designed to handle a high degree of uncertainty in the quantity and timing of arriving parcels, yet must also group and sort the parcels to meet tight departure deadlines. Thus motivated, this paper presents robust planning models that assign parcels to sort equipment while protecting against different sources of demand uncertainty commonly faced by parcel carriers. We demonstrate the computational viability of the proposed models using realistic-sized instances based on industry data, and show their value in providing sort plan alternatives that trade off operational costs and levels of robustness.

SDN and NFV for QoE-driven multimedia services delivery: The road towards 6G and beyond networks

The concept for developing the future mobile communication systems has been explored in recent years with a vision towards 5G and 6G systems. Meeting performance targets such as higher data rate transmission, lower end-to-end latency, higher capacity, lower cost, and satisfied Quality of Experience (QoE) for delivered services is the key for the success of 5G and 6G networks. Within these performance targets and associated enabling technologies, QoE and the overall management of multimedia services is the one which has been less well addressed for 5G in the past. This paper provides a comprehensive and ground-breaking discussion regarding QoE management in the context of future softwarized 5G/6G networks. We introduce a generalized QoE provisioning ecosystem for emerging multimedia streaming services in softwarized 5G/6G and beyond networks. We explore potential network softwarization and communication technologies that will enable the end-user’s QoE in 5G/6G. We further provide promising use case scenarios regarding (a) QoE-driven management of multimedia services over multi-access cloud/edge softwarized and virtualized 5G networks, (b) QoE monitoring for large traffic variations in business, residential and public areas in 5G networks, along with a Machine Learning (ML)-based softwarized controller for QoE provisioning over 5G/6G networks. We build on the achievements of 5G networks to provide the roadmap towards the development of 6G and beyond networks in terms of requirements, use case scenarios and service classes. We also present potential technologies that will be dominant through 2025–2030 in shaping the vision of 6G and beyond networks including (a) self-driving 3D network architecture, (b) network management, automation and orchestration, and (c) pervasive artificial intelligence. Moreover, we provide challenges and research directions in 6G and beyond wireless communication systems. The paper provides the first roadmap towards the management, orchestration and monitoring of multimedia 3D services in 6G and beyond networks. The comprehensive goal of this paper is to encourage researchers from the industry and academia to work together towards the realization of softwarized 6G and beyond networks while tackling the critical research challenges regarding the management of emerging 3D multimedia services and applications. The comments made by the authors in this paper are expectations on 6G, and the standardization of 6G where these aspects will be decided in 6G networks and beyond, will be started soon by different standardization bodies and fora.

Obligation to use the Brand and Legal Consequences of Non-Use

Ülkemizde, 1995 yılında kabul edilen dört ayrı Kanun Hükmünde Kararnameyle (KHK) korunan marka, patent-faydalı model, tasarım ve coğrafi işaretler, 6769 sayılı Sınai Mülkiyet Kanunu çatısı altında bir araya getirilmiştir. Dolayısıyla ülkemizde, Avrupa Birliği ile gümrük birliğinin kabulü ve yine Dünya Ticaret Örgütüne (DTÖ)/TRIPS’e taraf olunması nedeniyle doktrinde 1995 yılı nasıl bir milat olarak görülüyorsa, 10.1.2017 tarihinde yürürlüğe giren 6769 sayılı Sınai Mülkiyet Kanununun (SMK) kabulünün da bu alanda bir milat olarak görülmesi gerektiği söylenebilir. 
 Özellikle markanın kullanımı ile ilgili mehaz Avrupa Birliği düzenlemelerine paralellik gösteren düzenlemelerin hukuk sistemimize dâhil olması oldukça önemli bir hususu teşkil etmektedir. Seçtiği markayı marka siciline tescil ettirip, markayı Kanun’da öngörülen koşullarda kullanan marka sahibi, üçüncü kişilere karşı markasını koruyabilecektir. Sınai Mülkiyet Kanunu’nda bu kullanımın olması gereken şekli açıklanmış ve marka tescilli olduğu mal veya hizmetler sınıfında, Türkiye sınırları içerisinde ve ciddi bir biçimde kullanılması gerektiği vurgulanmıştır. Markanın gerçek kullanımı teşvik etmek ve markaların sicilde gereksiz olarak yer işgal etmesini engellemek amacıyla kanun tarafından markanın kullanılmasının zorunluluk hâline getirilmiştir. Sicile tescil ettirildiği tarihten itibaren beş sene içerisinde sahibi tarafından kullanılmayan veya kullanımına haklı bir sebep olmaksızın beş sene ara verilen markaların, ilgili kişilerine talebi üzerine TÜRKPATENT tarafından iptaline karar verilebilecektir. 
 Markanın kullanılması ile ilgili esaslar, 6769 sayılı Sınai Mülkiyet Kanunu 9/1. Maddesi hükmüne göre, “Tescil tarihinden itibaren beş yıl içinde haklı bir sebep olmadan tescil edildiği mal veya hizmetler bakımından marka sahibi tarafından Türkiye’de ciddi biçimde kullanılmayan ya da kullanımına beş yıl kesintisiz ara verilen markanın iptaline karar verilir”. Buna göre, tescil tarihinden itibaren beş yıl içinde, tescil edildiği mal veya hizmetler bakımından markanın, marka sahibi tarafından haklı bir neden olmadan, Türkiye’de ciddi biçimde kullanılamaması ya da kullanıma beş yıl kesintisiz ara verilmesi durumunda markanın iptaline karar verilir. Dolayısıyla, bu anlamda markanın iptaline karar verilmemesi için markanın marka sahibi tarafından, sicilde kaydolduğu mal veya hizmetler bakımından, temel işlevine uygun, ciddi olarak Türkiye’de kullanılması gerekmektedir. 
 Markanın ayırt edici karakteri değiştirilmeden farklı unsurlarla kullanılması, sadece ihracat amacıyla mal veya ambalajlarında kullanılması ve marka sahibinin izni ile kullanılması da SMK. 9/2 ve 3. fıkraları anlamında markayı kullanma kabul edilir. SMK’nin ilgili madde lafzından anlaşılmadığı ve kullanma kabul edilen hâllerin genişletilmesinin markanın kullanım zorunluluğunun getiriliş maksadıyla bağdaşmayacağı gerekçesiyle markayı kullanma sayılan hâller sayılı olup genişletilemeyeceği kabul edilmiştir. Nitekim Tekinalp, kullanım sayılan hâllerin ilgili kanun maddesinde sayılı olarak açıkça belirtildiği ve bu sayılı hâller dışında ekleme yapılmasının mümkün olmayacağını ifade etmiştir. 
 Bu makale çalışmasında bilhassa, markanın kullanım külfeti ve bu külfetin hukuki sonuçları üzerinde durulmaya çalışılmıştır. Çalışmada mevzuat hükümleri, yüksek mahkeme kararları, doktrin ve bilimsel çalışmalar ve uluslararası uygulamalar ve düzenlemelerden yararlanılmıştır

DISAGGREGATING THE DEMAND ELASTICITIES OF RAIL SERVICES AND ITS INFLUENCING FACTOR IN PAKISTAN

Public transport has become a challenge to supply on one side and to afford it on the other side. There are several issues in practical life, which can be associated with the demand for rail transport service, required for sustaining a normal life. This study is based on estimating the determinants of rail transport demand and calculating income and price elasticities for different classes of train services in the short run. The study found that the substitution is dominant and that the own-price effect and income effect are dominant in all the effects. There is a positive relationship between income increase and demand for rail service for air-condition class passengers. The study found that substitute elasticities are positive for rail services, which indicates that rail tracks and buses are substitutes for each other. It entails that rail fares income and road density are constraining variables such that the change in these would consequently bring a change in rail passengers in each class, and fuel price is also significantly reallocating the passenger across each class while the opposite does not hold. The increase in road accidents increases the demand for rail services in Pakistan. Keywords: Demand elasticities, Rail services, Short run, ARDL, and Road Accidents

SDN East–West cooperation in a converged fixed-mobile optical access network: enabling 5G slicing capabilities

The new 5G service requirements will force operators to rethink the deployment of infrastructure and management tools. The reuse of passive optical network (PON) technology to connect antenna sites has attracted the attention of some operators, as the high availability of some 5G services, as well as ubiquitous radio coverage in a denser network, could be ensured with minimum deployment efforts. In this case, the implications of each 5G slice instance deserve to be clarified in a PON infrastructure, and a fixed-mobile converged management system in optical access networks (ANs) will be necessary for operators. Some class of service (CoS) algorithms must be developed to ensure that different and heterogeneous services are properly transported through optical fibers in a fixed-mobile converged scenario. Many organizations are considering the use of transmission containers (T-CONTs) (the indicator of the bandwidth distribution in the PON uplink) for PON slicing, but the CoS for mobile traffic in a PON has not yet been defined. In parallel, the new AN management solutions are mostly focused on software-defined network (SDN) northbound/southbound interfaces between orchestrators and abstraction entities. However, if an end-to-end 5G slice instance must be dynamically applied in a fixed-mobile converged architecture, the coordination between mobile and residential management systems is necessary. We propose a disaggregated optical line terminal (OLT) with an SDN controller that leverages the advantages of virtualization technologies and the currently deployed OLT. We propose an East–West interface between fixed and mobile SDN controllers and have successfully implemented a 5G slicing proof of concept in access transport networks using this interface. We succeeded in reducing uplink latency and jitter by 25%–50% thanks to a smart optimization of T-CONTs, which could be interesting for ultrareliable and low-latency communications applications. A discussion of T-CONTs for slicing is also given based on experimental measurements.

The Place of Cultural Economy in Development Policies of Developing Countries: Van Province

Van city has serious socio-economic cultural development problems. Despite these problems, Van's cultural and natural diversity, as well as its potential to be an important commercial center due to its geopolitical situation, are important for the solution of extant problems. In this regard, this paper strives to examine the challenges of Van from the cultural aspect. Accordingly; in Van, the investments determined by the actors affecting the development and planning process periodically (2003-2016) were evaluated vis-à-vis the classification of cultural economy and human development index. Content analysis was used in the research. The European Union (EU) is one of the international actors in Van and the national actors are; Ministry of Development, Ministry of Interior, Ministry of Culture and Tourism, T.C. Prime Ministry General Directorate of Foundations, Eastern Anatolia Project (EAP) Regional Development Administration, Eastern Anatolia Development Agency (EADA) and Municipalities. It is seen that these are important actors in development policies and the investments they have made coincide with the strategies they have targeted. International actors prioritize social and human development investments within the framework of EU regional development policies. National actors however followed both a development model within the scope of industry, trade and services, which was predominantly based on the economic perspective, and a development model from the tourism perspective in the services class. Consequently, it is seen that development in Van is not directly evaluated from the cultural view, but evaluated together with tourism, culture is instrumentalized for tourism and cultural tourism is brought to the fore and cultural policies are developed from the tourism perspective.

GRAIN: Granular multi-label encrypted traffic classification using classifier chain

Granular traffic classification categorizes traffic into detailed classes like application names and services. Application names represent parent applications, such as Facebook, while application services are the individual actions within the parent application, such as Facebook-comment. These granular classes are still insufficient to keep pace with modern applications that offer various services. Accordingly, this paper further divides the application service class into inter-application and intra-application services to provide more insights. Inter-application service refers to a similar service between different parent applications, such as Facebook-comment and Youtube-comment, whereas intra-application service differentiates services within the same parent application, such as Facebook-comment and Facebook-post. Most studies focus on classification at the application name and inter-application service levels. In contrast, classification at the intra-application service level receives far less attention due to its complexity despite providing the highest flexibility. Therefore, this paper presents GRAIN, a granular multi-label approach to classify encrypted traffic at all three levels of granular classification: application name, inter-application and intra-application service levels using a classifier chain. GRAIN chains two random forest classifiers to produce a multi-label classification using seven novel statistical features based on packet payload length. The utilized features are independent of the packet payload content, thus unaffected by packet encryption and preserving user privacy. Our performance evaluation showed that GRAIN achieved an average F-measure of 99% at the application name level, 93% at the inter-application service level and 88% at the intra-application service level. To test for robustness, we compared GRAIN against four baseline classifiers and the ISCX VPN-nonVPN public dataset in which GRAIN maintained its comparable performance across all tests.

Implementation of Extra Efficient Bandwidth Utilization Dynamic Bandwidth Allocation Algorithm to Support Differentiated Service Classes in XGPON

The Dynamic Bandwidth Allocation (DBA) algorithm is required for efficient bandwidth utilization in XG-PON. The majority of existing DBA algorithms do not make use of the unused bandwidth of a queue with other service classes queue. In the update operation, the efficient bandwidth utilization (EBU) method employs a Borrow Refund (BR) method to utilize unused bandwidth between traffic class queues. This paper presents an extra efficient bandwidth utilization (EEBU) algorithm, which overcomes the limitations mentioned above with proper polling and scheduling mechanism. The theoretical and simulation results show that EEBU improvements for T-CONT 2 delay are 1% and 10%, and for T-CONT 3 delay are 8% and 22%, and for T-CONT 4 delay by 6% and 4.5% compared to the EBU and Giga PON access network (GIANT) respectively.

Priority-based load-adaptive preamble separation random access for QoS-differentiated services in 5G networks

Fifth generation (5G) networks provide connectivity for several services including enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC) and massive Internet of things (mIoT). With the accelerated increase in the number of devices connected to the networks, and the diversity in quality-of-service (QoS) requirements, an appropriate modification in protocol design is required. Initial access in 5G networks is carried out based on the random access (RA) procedure through the random access channel (RACH). However, the limited resources, i.e. preambles, of the RACH causes intensive collisions among the massive number of contending devices, which result in low success probability and high access delay, causing failure to meet QoS requirements for different services. This paper introduces a priority-based load-adaptive preamble separation (PLPS) RA scheme in which RACH resources are separated between devices according to the service class priority and load estimation. The number of preambles assigned for each class of device is updated before each random access opportunity (RAO), based on the arrival load estimation, aimed at increasing the RACH throughput and therefore reducing the access delay for eMBB and URLLC devices. The proposed scheme is evaluated through a mathematical analysis model and extensive simulations. The results show that the proposed PLPS RA scheme succeeds in achieving the different QoS requirements of the three considered services, while increasing the RACH throughput by approximately 140%, compared to the benchmark which indicates the efficiency of the proposed scheme.

A Geometric Backoff Time Distribution of IEEE 802.11 DCF: An Analytical Study

Today’s networks, including WLANs, transportdifferent classes of service. A service differentiation is thenessential to provide QoS. However, IEEE 802.11 for WLANs wasprimarily designed for best effort traffic and did not provide QoSspecifications. IEEE 802.11e MAC has been then described tosupport QoS in WLAN. In this paper, we propose a new schemefor service differentiation which is based on the 802.11 standardand requires minor modifications. In fact, we act on DCF whichuses the backoff procedure to solve contention in WLANs.For this scheme, we use, instead of the uniform distribution,a geometric distribution for random backoff time selection.Using a multi-class system, we propose three parametrizationsof the geometric distribution which imply different dynamicdifferentiation modes and we provide an analytical study, usinga Markov chain model, to compare our differentiation modes.We discuss our numerical results which give the performancesevaluation of the proposed mechanism in term of throughputand delay.