Multiple-parameter coupling metrics for layered component-based software

Coupling represents the degree of interdependence between two software components. Understanding software dependency is directly related to improving software understandability, maintainability, and reusability. In this paper, we analyze the difference between component coupling and component dependency, introduce a two-parameter component coupling metric and a three-parameter component dependency metric. An important parameter in both these metrics is coupling distance, which represents the relevance of two coupled components. These metrics are applicable to layered component-based software. These metrics can be used to represent the dependencies induced by all types of software coupling. We show how to determine coupling and dependency of all scales of software components using these metrics. These metrics are then applied to Apache HTTP, an open-source web server. The study shows that coupling distance is related to the number of modifications of a component, which is an important indicator of component fault rate, stability and subsequently, component complexity.

An expiration age-based document placement scheme for cooperative Web caching

The sharing of caches among proxies is an important technique to reduce Web traffic, alleviate network bottlenecks, and improve response time of document requests. Most existing work on cooperative caching has been focused on serving misses collaboratively. Very few have studied the effect of cooperation on document placement schemes and its potential enhancements on cache hit ratio and latency reduction. We propose a new document placement scheme which takes into account the contentions at individual caches in order to limit the replication of documents within a cache group and increase document hit ratio. The main idea of this new scheme is to view the aggregate disk space of the cache group as a global resource of the group and uses the concept of cache expiration age to measure the contention of individual caches. The decision of whether to cache a document at a proxy is made collectively among the caches that already have a copy of this document. We refer to this new document placement scheme as the Expiration Age-based scheme (EA scheme). The EA scheme effectively reduces the replication of documents across the cache group, while ensuring that a copy of the document always resides in a cache where it is likely to stay for the longest time. We report our study on the potentials and limits of the EA scheme using both analytic modeling and trace-based simulation. The analytical model compares and contrasts the existing (ad hoc) placement scheme of cooperative proxy caches with our new EA scheme and indicates that the EA scheme improves the effectiveness of aggregate disk usage, thereby increasing the average time duration for which documents stay in the cache. The trace-based simulations show that the EA scheme yields higher hit rates and better response times compared to the existing document placement schemes used in most of the caching proxies.     

AWJ machinability performance of CS/UPR composites with the effect of chemical treatment

This work focuses on the effect of chemical treatment of coconut sheath/unsaturated polyester (CS/UPR) composite on the performance of abrasive waterjet machining (AWJM). Two different chemical treatments, namely alkali (NaOH) and trichlorovinylsilane, were imposed on the CS fiber. Further, the induced compressive strength arising as a result of AWJM was studied along the radial and depth directions of the composite. Experimental results revealed significantly lower induced stress at all points compared to the ultimate stress of CS/UPR composites except the free-edge loading condition. The chemically treated composites also exhibited inconsistent results in the machining characteristics such as kerf taper angle (T_a) and surface roughness (R_a) under varying cutting conditions. However, no direct correlation was seen between interfacial adhesion and T_a and R_a of the cutting zone. The maximum decrease of 12% of T_a and 22% of R_a was found for silane-treated composites compared to the untreated ones. In addition, the composite failure mechanisms such as fiber pullout, fiber breakage, interfacial debonding, matrix failure, and voids were identified in the cutting surfaces through scanning electron microscopy analysis.     

A methodological review on attack and defense strategies in cyber warfare

Cyberspace is an integration of cyber physical system components that integrates computation, networking, physical processes, embedded computers and network monitors which uses feedback loops for controlling the processes where the computations are affected by processes and vice versa. More general, cyber physical systems include all equipments operated on preprogrammed instructions ranging from simple electronic devices to the ultra-modern warfare equipments along with life saving devices. Active cyber-attacks can cause cyber warfare situations by disrupting an entire community of people, which in turn raises an emergency situation to the nation. Thus, cyber warfare is a major threat to the nation at large. In this paper, we analyze the various aspects of cyber warfare situations and a survey on ongoing attacks, defense and cyber forensics strategies in that field. Internet of Things (IoT) is an emerging computing area which enables Machine to Machine communication in cyber physical systems. An attack on IoT causes major issues to the security on the devices and thus, the various threats and attacks on IoT are analyzed here. Overall monitoring and data acquisition in cyber physical systems is done by Supervisory Control and Data Acquisition systems and are mainly targeted by the attackers in order to leave the cyberspace applications not functioning. Therefore, the various threats, attacks and research issues pertaining to the cyberspace are surveyed in this paper along with a few research issues and challenges that are to be solved in the area of cyber warfare.

     

Digital document analytics using logistic regressive and deep transition-based dependency parsing

The selection of text features is a fundamental task and plays an important role in digital document analysis. Conventional methods in text feature extraction necessitate indigenous features. Obtaining an efficient feature is an extensive process, but a new and real-time representation of features in text data is a challenging task. Deep learning is making inroads in digital document mining. A significant distinction between deep learning and traditional methods is that deep learning learns features in a digital document in an automatic manner. In this paper, logistic regression and deep dependency parsing (LR-DDP) methods are proposed. The logistic regression token generation model generates robust tokens by means of Napierian grammar. With the robust generated tokens, a deep transition-based dependency parsing using duplex long short-term memory is designed. Experimental results demonstrate that our dependency parser achieves comparable performance in terms of digital document parsing accuracy, parsing time and overhead when compared to existing methods. Hence, these methods are found to be computationally efficient and accurate.

     

Properties of extrusion cast sheets of blends of natural and aliphatic polyesters

Natural and synthetic polymers of various compositions were blended in a twin‐screw extruder. These blends were then sheeted into thin sheets with a coat hanger die attached to a single‐screw extruder. The natural content in the blend was varied between 5 and 50 wt %, and the mechanical and morphological properties of the blends were evaluated. At 50 wt % natural content, the tensile strength decreased to a third of that of the synthetic polymer. The use of a compatibilizer doubled the tensile strength for the 50 wt % natural content blend. The sheets displayed equal strengths in the machine and transverse direction. The tear strength decreased as the natural content increased, and the decrease was greater in the anhydride‐compatibilized blends than in the uncompatibilized blends. The blends displayed two distinct glass transitions, one for each component, indicating phase separation. The crystallinity of the blends decreased as the starch content increased. This result was confirmed by differential scanning calorimetry (DSC), which showed that the melting endotherm decreased as the starch content increased. Gel permeation chromatography (GPC) results showed that the peak position was at the same location irrespective of blend composition, indicating minimal degradation of starch moieties. The water absorption was diffusion controlled, with a sharp initial burst of water uptake. Scanning electron microscopy (SEM) showed melting of starch granules that formed a co‐continuous phase with the synthetic polyester. Increasing the natural content also increased the surface roughness of the sheets. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1545–1554, 2003     

Method to Characterize the Air Flow and Water Removal Characteristics during Vacuum Dewatering. Part I—Experimental Method

An experimental method using a novel design to characterize the air flow and water removal during vacuum dewatering in paper manufacturing is discussed. The experimental setup involves the intermittent application of vacuum, similar to commercial systems, using a rotating disk with slot opening arrangement. The system is capable of commercially realistic residence times of the order of milliseconds. The intermittent application of vacuum simulates vacuum dewatering on commercial paper machines. The air flow rate is calculated from changes in pressure and temperature in the vacuum tank underneath the sample. The role and importance of air flow during vacuum dewatering is studied by accurately measuring the air flow, properly taking into account the leaks during vacuum dewatering. The method described here provides for the first time accurate air flow and water removal data during vacuum dewatering. Methods of analysis of the experimental data are also presented. This information can be used to better understand the water removal process as well the role and importance of air flow during vacuum dewatering.     

Analysis of network processing workloads

Network processing is becoming an increasingly important paradigm as the Internet moves towards an architecture with more complex functionality in the data path. Modern routers not only forward packets, but also process headers and payloads to implement a variety of functions related to security, performance, and customization. It is important to get a detailed understanding of the workloads associated with this processing in order to be able to develop efficient network processing engines. We present a tool called PacketBench, which provides a framework for implementing network processing applications and obtaining an extensive set of workload characteristics. For statistics collection, PacketBench provides the ability to derive a number of microarchitectural and networking related metrics. We show a range of workload results that focus on individual packets and the variation between them. The understanding of workload details of network processing has many practical applications. We discuss how PacketBench results can be used to estimate network processing delay that are very close to those obtained from measurement.     

Reactive Alder‐ene blend of diallyl bisphenol A novolac and bisphenol A bismaleimide: synthesis,cure and adhesion studies

A novel, addition‐curable novolac resin (ABPF) was synthesized by the reaction of diallyl bisphenol A with formaldehyde using p‐toluene sulfonic acid as the catalyst. The synthesis conditions were optimized to obtain soluble polymer of desirable molecular weight distribution which was characterized by FT‐IR, NMR and SEC. ABPF was reactively blended with bisphenol A bismaleimide (BMIP) and cured through an Alder‐ene reaction at high temperatures. The cure characteristics of BMIP–ABPF blend with a maleimide:allyl phenol stoichiometry of 1:1 were studied using FT‐IR, DSC and DMA, which evidenced the multi‐step cure reactions taking place in the system. Cure optimization was evaluated by DSC, DMA and adhesive property tests. The moderately crosslinked blend was conducive for achieving the optimum adhesive properties on aluminium substrates. Retention of the adhesive properties was greater than 100% at 150 °C. © 2001 Society of Chemical Industry     

Mentoring object-oriented projects

In mentoring, an experienced person (the mentor) undertakes to guide a less experienced person (the “mentee”) in the same or similar field. Mentoring can effectively bring an organization up to speed with new technology. What loosely distinguishes mentoring from training is that the latter is something often associated with a classroom. With mentoring, the learning happens on the job: a mentor educates by continuously hand-holding the mentee on the latter's tasks. Of course, in any real situation the education process must involve a judicious and inseparable mix of training and mentoring, with the same person often performing both roles. You can apply mentoring to people in your organization or even in a customer organization; the article focuses on the former. Mentors are particularly crucial for an organization learning object orientation. The author presents lessons learned from his experiences as a mentor on object oriented application development projects. He attempts to generalize his observations and present them as succinct, shop-usable advice, not just for the mentor but for the mentee as well