Foundational Theory for Understanding Policy Routing Dynamics

In this paper we introduce a theory of policy routing dynamics based on fundamental axioms of routing update mechanisms. We develop a dynamic policy routing model (DPR) that extends the static formalism of the stable paths problem (introduced by Griffin et al.) with discrete synchronous time. DPR captures the propagation of path changes in any dynamic network irrespective of its time-varying topology. We introduce several novel structures such as causation chains, dispute fences and policy digraphs that model different aspects of routing dynamics and provide insight into how these dynamics manifest in a network. We exercise the practicality of the theoretical foundation provided by DPR with two fundamental problems: routing dynamics minimization and policy conflict detection. The dynamics minimization problem utilizes policy digraphs, that capture the dependencies in routing policies irrespective of underlying topology dynamics, to solve a graph optimization problem. This optimization problem explicitly minimizes the number of routing update messages in a dynamic network by optimally changing the path preferences of a minimal subset of nodes. The conflict detection problem, on the other hand, utilizes a theoretical result of DPR where the root cause of a causation cycle (i.e., cycle of routing update messages) can be precisely inferred as either a transient route flap or a dispute wheel (i.e., policy conflict). Using this result we develop SafetyPulse, a token-based distributed algorithm to detect policy conflicts in a dynamic network. SafetyPulse is privacy preserving, computationally efficient, and provably correct.National Science Foundation (CISE/CCF 0820138, CISE/CSR 0720604, CISE/CNS 0524477, CNS/ITR 0205294, CISE/EIA RI #0202067

Management of Big Annotations in Relational Database Management Systems

Annotations play a key role in understanding and describing the data, and annotation management has become an integral component in most emerging applications such as scientific databases. Scientists need to exchange not only data but also their thoughts, comments and annotations on the data as well. Annotations represent comments, Lineage of data, description and much more. Therefore, several annotation management techniques have been proposed to efficiently and abstractly handle the annotations. However, with the increasing scale of collaboration and the extensive use of annotations among users and scientists, the number and size of the annotations may far exceed the size of the original data itself. However, current annotation management techniques don’t address large scale annotation management. In this work, we propose three chapters to that tackle the Big annotations from three different perspectives (1) User-Centric Annotation Propagation, (2) Proactive Annotation Management and (3) InsightNotes Summary-Based Querying. We capture users\u27 preferences in profiles and personalizes the annotation propagation at query time by reporting the most relevant annotations (per tuple) for each user based on time plan. We provide three Time-Based plans, support static and dynamic profiles for each user. We support a proactive annotation management which suggests data tuples to be annotated in case new annotation has a reference to a data value and user doesn’t annotate the data precisely. Moreover, we provide an extension on the InsightNotes: Summary-Based Annotation Management in Relational Databases by adding query language that enable the user to query the annotation summaries and add predicates on the annotation summaries themselves. Our system is implemented inside PostgreSQL

On the Interaction between TCP and the Wireless Channel in CDMA2000 Networks

In this work, we conducted extensive active measurements on a large nationwide CDMA2000 1xRTT network in order to characterize the impact of both the Radio Link Protocol and more importantly, the wireless scheduler, on TCP. Our measurements include standard TCP/UDP logs, as well as detailed RF layer statistics that allow observability into RF dynamics. With the help of a robust correlation measure, normalized mutual information, we were able to quantify the impact of these two RF factors on TCP performance metrics such as the round trip time, packet loss rate, instantaneous throughput etc. We show that the variable channel rate has the larger impact on TCP behavior when compared to the Radio Link Protocol. Furthermore, we expose and rank the factors that influence the assigned channel rate itself and in particular, demonstrate the sensitivity of the wireless scheduler to the data sending rate. Thus, TCP is adapting its rate to match the available network capacity, while the rate allocated by the wireless scheduler is influenced by the sender's behavior. Such a system is best described as a closed loop system with two feedback controllers, the TCP controller and the wireless scheduler, each one affecting the other's decisions. In this work, we take the first steps in characterizing such a system in a realistic environment

TCP over CDMA2000 Networks: A Cross-Layer Measurement Study

Modern cellular channels in 3G networks incorporate sophisticated power control and dynamic rate adaptation which can have significant impact on adaptive transport layer protocols, such as TCP. Though there exists studies that have evaluated the performance of TCP over such networks, they are based solely on observations at the transport layer and hence have no visibility into the impact of lower layer dynamics, which are a key characteristic of these networks. In this work, we present a detailed characterization of TCP behavior based on cross-layer measurement of transport layer, as well as RF and MAC layer parameters. In particular, through a series of active TCP/UDP experiments and measurement of the relevant variables at all three layers, we characterize both, the wireless scheduler and the radio link protocol in a commercial CDMA2000 network and assess their impact on TCP dynamics. Somewhat surprisingly, our findings indicate that the wireless scheduler is mostly insensitive to channel quality and sector load over short timescales and is mainly affected by the transport layer data rate. Furthermore, with the help of a robust correlation measure, Normalized Mutual Information, we were able to quantify the impact of the wireless scheduler and the radio link protocol on various TCP parameters such as the round trip time, throughput and packet loss rate

The Nature of Human Avarice in Ben Jonson's Volpone

Throughout history, avarice has always been an important topic in works of literature. This human desire for more of something and the craving to accumulate more and more wealth; and to hold on to what one has accumulated  has always been the focus point of writers since the Greek antiquity and the myth of Midas' lust for gold is a case in point. The goal of this article is to investigate and discuss Ben Jonson's portrayal of this motif in one of his plays; namely, "Volpone". Keywords: Nature of Human Avarice, Volpone, portraya

Customers' Switching Barrier on Switching Behavior from Conventional Banks to Sharia Banks

This study aims to explore the reasons why conventional bank customers have not yet shifted to Islamic (sharia) banking in South Sulawesi, as well as identify the obstacles that have caused customers to remain conventional banks. The research subjects numbered 110 people. The research method uses Mixed Methods with sequential exploratory design. The first stage is a qualitative method to obtain data that is variable because the community has not yet switched to sharia banking. The second stage of the quantitative method is using Factor Analysis, to deepen the data and test the data so that the findings can be generalized. Data were collected by open and closed questionnaires and interviews, validity and reliability tests were carried out based on the analysis model used. The results of the analysis show that the factors that constrain people to move to Sharia banking are Fee Interest Factor, Information Factor, Location Factor, Relationship and Reputation Factor, Religiosity Factors, Product Factor, and Financial Risk Cost Factor. There are four findings of new factors as novelty of this study, namely Fee Interest Factors, Location Factors, Religiousity Factors, and Product Factors, as barriers to switch for the service industry, especially Sharia banking

Experimental and Numerical Study on the Hydrodynamic Performance of Suspended Curved Breakwaters

The purpose of breakwaters is to protect the ports, beaches, or beach facilities from strong waves and storms, as they help establish calm inside the port and thus achieve safety for ships and ease of operation. This paper presents an experimental and numerical study of unconventional alternatives to the vertical breakwater in order to evaluate the hydrodynamic performance of the proposed models. Two proposed cases for a semi-submerged breakwater were selected in the form of a half-pipe section with an inside diameter of 20 cm and a thickness of 1 cm. Case (a) was of the concave type of semicircular breakwater, while case (b) was of the convex type. Numerical modeling FLOW 3D was used to construct numerous scenarios for numerical simulation of the proposed breakwaters. The obtained results indicates that, when comparing the wave transmission coefficient (Kt) and its reflection coefficient (Kr) with the relative water depth (h/L), the transmission coefficient decreased with the relative height of the wave, while the reflection coefficient was completely reversed. In case (a), Kt was less than in case (b) at a range of 10% to 15%, while Kr in case (a) was bigger than in case (b) at a range of 5% to 10%. When the wave hit the breakwater, it was reflected back as its energy is dissipated in less water depth and its speed decreases as it approaches the port. The velocity of the wave decreases as it approaches the bottom, which means that the wave is affected by the depth of the water, i.e. the lower the water depth, the lower the wave velocity. Case (a) was more efficient and effective in wave dissipation, current velocity, and bed stability than case (b), so it is recommended to use case (a) due to its efficiency in protecting coastal areas and generating electricity

Study of Unconventional Alternatives to Vertical Breakwater

The main objective of the breakwaters is to protect the port, the beach or the beach facilities from strong waves and storms, as they help to establish calm inside the port and thus achieve safety for ships, and ease of operation. This research aims to present study unconventional alternatives to vertical breakwater. In this study, two different models of vertical wave barriers implemented were chosen for their study and evaluation of the hydrodynamic performance. The first model is a vertical wall with circular slots and the second model is a vertical wall with square slots. A comparison was made between the two models it was found that the square slots reduce the transmission of waves more than circular slots by 5 to 20%. The use of two circular slotted walls decreases wave transmission by up to 30% and increases wave energy dissipation by up to 40% as compared to a single wall. With increasing relative length (h/L), the horizontal wave force rises. The relative wave forces (F/Fo), at porosity ( ) =0.25, was greater than at porosity ( ) = 0.50 by 10 to 30%. At the openings, the wave velocity is high, and the wave energy dissipation factor was also high; the higher the wave amplitude, the greater the wave energy dissipation factor

The division free parallel algorithm for finding determinant

A cross multiplication method for determinant was generalized for any size of square matrices using a new permutation strategy.The permutation is generated based on starter sets.However, via permutation, the time execution of sequential algorithm became longer.Thus, in order to reduce the computation time, a parallel strategy was developed which is suited for master and slave paradigm of the high performance computer.A parallel algorithm is integrated with message passing interface.The numerical results showed that the parallel methods computed the determinants faster than the sequential counterparts particularly when the tasks were equally allocated

Analisis lakuan bahasa direktif guru pelatih dalam komunikasi di bilik darjah

Sewaktu proses pengajaran dan pembelajaran berlangsung, pelbagai lakuan bahasa digunakan oleh guru pelatih untuk menyampaikan isi pelajaran. Antara lakuan bahasa yang kerap digunakan dalam kalangan guru pelatih sewaktu mengajar ialah lakuan bahasa direktif. Lakuan bahasa direktif ialah ujaran yang digunakan membuat si pendengar melakukan sesuatu. Sehubungan itu, kajian ini meneliti bentuk lakuan bahasa direktif guru pelatih Institut Pendidikan Guru Malaysia (IPGM) dalam komunikasi di bilik darjah sewaktu mengajar matapelajaran Bahasa Melayu. Kajian secara kualitatif ini menggunakan teknik rakaman melibatkan tiga orang guru pelatih tahun akhir IPGM sebagai responden kajian. Ujaran lakuan bahasa direktif telah ditranskripsikan secara verbatim dan dianalisis menggunakan teori lakuan pertuturan dan komunikasi oleh Bach dan Harnish (1979). Kajian menunjukkan ujaran direktif responden terdiri daripada subkategori lakuan bahasa direktif permintaan, pertanyaan, keperluan, larangan, permisif dan nasihat. Kajian ini juga mendapati, dalam subkategori lakuan bahasa direktif, ujaran direktif berbentuk keperluan yang terdiri daripada ayat suruhan paling kerap diujarkan oleh guru pelatih. Hal ini kerana direktif keperluan dapat menyerlahkan kewibawaan dan ketegasan si penutur kepada pihak pendengar. Kesimpulannya, kajian menunjukkan bahawa guru pelatih IPGM mempunyai kecekapan pragmatik dalam komunikasi di bilik darjah terutama sewaktu memberikan arahan kepada murid