Virtual RTCP: A Case Study of Monitoring and Repair for UDP-based IPTV Systems

IPTV systems have seen widespread deployment, but often lack robust mechanisms for monitoring the quality of experience. This makes it difficult for network operators to ensure that their services match the quality of traditional broadcast TV systems, leading to consumer dissatisfaction. We present a case study of virtual RTCP, a new framework for reception quality monitoring and reporting for UDP-encapsulated MPEG video delivered over IP multicast. We show that this allows incremental deployment of reporting infrastructure, coupled with effective retransmission-based packet loss repair

Issues of Interaction of Penitentiary Agencies and Institutions with the Departments on Combating Crime in Ukraine and Poland

Bailov, A. V. Issues of Interaction of Penitentiary Agencies and Institutions with the Departments onCombating Crime in Ukraine and Poland [Електронний ресурс] / Anton V. Bailov, Ivan O. Romanchuk // Журнал східноєвропейського права. – 2017. – № 38. – С. 5-11. – Режим доступу: http://easternlaw.com.ua/wp-content/uploads/2017/04/romanchuk_bailov_38.pdfУ статті аналізуються питання взаємодії пенітенціарних органів та установ з іншими правоохоронними органами України та Польщі. Автори вказують, що боротьба зі злочинністю є спільною метою всіх правоохоронних органів, яка досягається тільки шляхом взаємодії останніх один з одним. Визначено форми взаємодії пенітенціарних органів та установ з підрозділами по боротьбі зі злочинністю в Україні та Польщі. Автори виконали порівняльний аналіз законодавства обох країн з цього питання і розробили деякі пропозиції щодо його удосконалення.The issues of interaction of penitentiary agencies and institutions with other law enforcement agencies in Ukraine and Poland have been analyzed in the article. The authors point out that crime combating is the common objective of all law enforcement agencies, which is achieved only by the way of interaction of the latter between each other. Forms of interaction of penitentiary agencies and institutions with the departments on combating crime in Ukraine and Poland have been determined. The authors have accomplished the comparative analysis of the legislation of both countries regarding this issue and has elaborated some propositions on its improvement. The authors emphasize that crime combating is one of the most important components of functioning and development of any state; it is an instrument that assists the society to be steadily developed and to be secured. Considering stated above we can confirm that fighting (combating) against crime is one of the main overall objectives of law enforcement agencies in the state. Therefore, the activities of all law enforcement agencies along with direct functions provided by the legislation are somehow reduced to one common objective – combating crime. This is also related to penitentiary agencies and institutions that are law enforcement agencies as well. To analyze the processes of interaction of penitentiary agencies and institutions with the departments on combating crime in Ukraine and Poland the authors consider it necessary to determine what kind of law enforcement agencies operate in both countries and what system of penitentiary agencies and institutions is functioning in these countries. Therefore, the issues of interaction of penitentiary agencies and institutions with other law enforcement agencies in Ukraine and Poland have been analyzed in the article. The authors point out that crime combating as the common objective of all law enforcement agencies is achieved only by the way of the interaction of the latter between each other. Forms of interaction of penitentiary agencies and institutions with the departments on combating crime in Ukraine and Poland have been determined. The authors have accomplished the comparative analysis of the legislation of both countries regarding this issue and has elaborated some propositions on its improvement.В статье анализируются вопросы взаимодействия пенитенциарных органов и учреждений с другими правоохранительными органами Украины и Польши. Авторы указывают, что борьба с преступностью является общей целью всех правоохранительных органов, которая достигается только путем взаимодействия последних друг с другом. Определены формы взаимодействия пенитенциарных органов и учреждений с подразделениями по борьбе с преступностью в Украине и Польше. Авторы выполнили сравнительный анализ законодательства обеих стран по этому вопросу и разработали некоторые предложения по его усовершенствованию

Preliminary Results Towards Contract Monitorability

This paper discusses preliminary investigations on the monitorability of contracts for web service descriptions. There are settings where servers do not guarantee statically whether they satisfy some specified contract, which forces the client (i.e., the entity interacting with the server) to perform dynamic checks. This scenario may be viewed as an instance of Runtime Verification, where a pertinent question is whether contracts can be monitored for adequately at runtime, otherwise stated as the monitorability of contracts. We consider a simple language of finitary contracts describing both clients and servers, and develop a formal framework that describes server contract monitoring. We define monitor properties that potentially contribute towards a comprehensive notion of contract monitorability and show that our simple contract language satisfies these properties.Comment: In Proceedings PrePost 2016, arXiv:1605.0809

Modernisation and the dynamics of welfare governance

The modernisation of welfare states is high on the agenda of many European nations. The so-called "anglo-saxon" model plays an important, but contradictory, symbolic role, as both a template for reform and as a symbol of the problems of neo-liberal governance. Rather than viewing the UK as an exemplar of neo liberalism, this paper highlights the unstable mix of governance styles at stake in welfare reform. It highlights current trends in the attempt to remake relationships between government and people around new conceptions of citizenship and community and the fostering of new aspirations and opportunities. It then explores the implications for issues of governance around the themes of welfare, work and citizenship. Finally the paper identifies some problems inherent in new discourses of the social - including social inclusion and social investment - that are at the core of welfare state modernisation strategies in the UK and beyond

Fuzzy Logic Control of Adaptive ARQ for Video Distribution over a Bluetooth Wireless Link

Bluetooth's default automatic repeat request (ARQ) scheme is not suited to video distribution resulting in missed display and decoded deadlines. Adaptive ARQ with active discard of expired packets from the send buffer is an alternative approach. However, even with the addition of cross-layer adaptation to picture-type packet importance, ARQ is not ideal in conditions of a deteriorating RF channel. The paper presents fuzzy logic control of ARQ, based on send buffer fullness and the head-of-line packet's deadline. The advantage of the fuzzy logic approach, which also scales its output according to picture type importance, is that the impact of delay can be directly introduced to the model, causing retransmissions to be reduced compared to all other schemes. The scheme considers both the delay constraints of the video stream and at the same time avoids send buffer overflow. Tests explore a variety of Bluetooth send buffer sizes and channel conditions. For adverse channel conditions and buffer size, the tests show an improvement of at least 4 dB in video quality compared to nonfuzzy schemes. The scheme can be applied to any codec with I-, P-, and (possibly) B-slices by inspection of packet headers without the need for encoder intervention.</jats:p

Multipath streaming: fundamental limits and efficient algorithms

We investigate streaming over multiple links. A file is split into small units called chunks that may be requested on the various links according to some policy, and received after some random delay. After a start-up time called pre-buffering time, received chunks are played at a fixed speed. There is starvation if the chunk to be played has not yet arrived. We provide lower bounds (fundamental limits) on the starvation probability of any policy. We further propose simple, order-optimal policies that require no feedback. For general delay distributions, we provide tractable upper bounds for the starvation probability of the proposed policies, allowing to select the pre-buffering time appropriately. We specialize our results to: (i) links that employ CSMA or opportunistic scheduling at the packet level, (ii) links shared with a primary user (iii) links that use fair rate sharing at the flow level. We consider a generic model so that our results give insight into the design and performance of media streaming over (a) wired networks with several paths between the source and destination, (b) wireless networks featuring spectrum aggregation and (c) multi-homed wireless networks.Comment: 24 page

SMT-based Verification of LTL Specifications with Integer Constraints and its Application to Runtime Checking of Service Substitutability

An important problem that arises during the execution of service-based applications concerns the ability to determine whether a running service can be substituted with one with a different interface, for example if the former is no longer available. Standard Bounded Model Checking techniques can be used to perform this check, but they must be able to provide answers very quickly, lest the check hampers the operativeness of the application, instead of aiding it. The problem becomes even more complex when conversational services are considered, i.e., services that expose operations that have Input/Output data dependencies among them. In this paper we introduce a formal verification technique for an extension of Linear Temporal Logic that allows users to include in formulae constraints on integer variables. This technique applied to the substitutability problem for conversational services is shown to be considerably faster and with smaller memory footprint than existing ones