Computer Science Journal (AGH University of Science and Technology, Krakow)
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The Cryptanalysis of the Enigma Cipher. The Plugboard and the Cryptologic Bomb.
Get PDFWe study the problem of decoding secret messages encrypted by the German Army with the M3 Enigma machine after September 15, 1938. We focused our attention on the algorithmization and programming of this problem. A completion and optimization of Zygalski’s sheets method were presented previously. We describe below the missing algorithm solving the problem of the plugboard settings with an algebraic justification. This method is the original idea of the authors, and we can use it for cryptanalysis together with both Zygalski’s sheets method and Rejewski’s bomb method. Next, we present a reconstruction of the cryptologic bomb. We enclose an implementation of both algorithms in Cpp language
Resource Storage Management Model for Ensuring Quality of Service in the Cloud Archive Systems
Get PDFNowadays, service providers offer a lot of IT services in the public or private cloud. The client can buy various kinds of services like SaaS, PaaS, etc. Recently there was introduced Backup as a Service (BaaS) as a variety of SaaS. At the moment there are available several different BaaSes for archiving the data in the cloud, but they provide only a basic level of service quality. In the paper we propose a model which ensures QoS for BaaS and some methods for management of storage resources aimed at achieving the required SLA. This model introduces a set of parameters responsible for SLA level which can be offered on the basic or higher level of quality. The storage systems (typically HSM), which are distributed between several Data Centres, are built based on disk arrays, VTLs, and tape libraries. The RSMM model does not assume bandwidth reservation or control, but is rather focused on the management of storage resources
Public cloud computing for Software as a Service platforms
Get PDFAs cloud computing becomes increasingly popular among enterprises, organizations and developers, it is time to consider how Software as a Service solutions can be built rapidly and cost effectively. This paper presents the possibility of using a service-based architecture operating within the framework of the public cloud computing model and implementing Software as a Service. It also describes the architecture, implementation and testing of sample applications. The conclusions drawn with respect to related work and the results obtained shed more light on the application of public cloud systems for Software as a Service purposes
Agent-based Data Integration Framework
Get PDFCombining data from diverse, heterogeneous sources while facilitating a unified access to it is an important (albeit difficult) task. There are various possibilities of performing it. In this publication, we propose and describe an agent-based framework dedicated to acquiring and processing distributed, heterogeneous data collected from diverse sources (e.g., the Internet, external software, relational, and document databases). Using this multi-agent-based approach in the aspects of the general architecture (the organization and management of the framework), we create a proof-of-concept implementation. The approach is presented using a sample scenario in which the system is used to search for personal and professional profiles of scientists
EFFICIENT IMPLEMENTATION OF BRANCH-AND-BOUND METHOD ON DESKTOP GRIDS
Get PDFThe Berkeley Open Infrastructure for Network Computing (BOINC) is an opensource middleware system for volunteer and desktop grid computing. In this paper we propose BNBTEST, a BOINC version of distributed branch and bound method. The crucial issues of distributed branch-and-bound method are traversing the search tree and loading balance. We developed subtaskspackaging method and three dierent subtasks\u27 distribution strategies to solve these
Context Aware Handover Algorithms for Mobile Positioning Systems
Get PDFAbstract: This work proposes context aware handover algorithms for mobile positioning systems. The algorithms perform handover among positioning systems based on important contextual factors related to position determination with efficient use of battery. The proposed solution which consists of the algorithms is implemented in the form of an Android application named Locate@nav6. The performance of the proposed solution was tested in selected experimental areas. The handover performance was compared with other existing location applications. The proposed solution performed correct handover among positioning systems in 95% of cases studied while two other applications performed correct handover in only 50% of cases studied. Battery usage of the proposed solution is less than one third of the battery usage of two other applications. The analysis of the positioning error of the applications demonstrated that, the proposed solution is able to reduce positioning error indirectly by handing over the task of positioning to an appropriate positioning system. This kept the average error of positioning below 42.1 meters for Locate@nav6 while the average error for two other applications namely Google Latitude and Malaysia maps was between 92.7 and 171.13 meters
Network management services based on the OpenFlow environment
Get PDFThe subject of this article is network management through web service calls, which allows software applications to exert an influence on network traffic. In this manner, software can make independent decisions concerning the direction of requests so that they can be served as soon as possible. This is important because only proper cooperation including all architecture layers can ensure the best performance, especially when software that largely depends on computer networks and utilizes them heavily is involved. To demonstrate that the approach described above is feasible and can be useful at the same time, this article presents a switch-level load balancer developed using OpenFlow. Client software communicates with the balancer through REST web service calls, which are used to provide information on current machine load and its ability to serve incoming requests. The result is a cheap, highly customizable and extremely fast load balancer with considerable potential for further development
Acceptance Testing of Web Applications with Test Description Language
Get PDFAcceptance tests are usually created by a client after a part of a system is implemented. However, some methodologies propose the elaboration of test cases before implementing a system. This approach increases the probability of system implementation that fulfills requirements, but may be problematic for customers and testers. To allow acceptance testing in such conditions, we propose to define test cases by recording them on an interactive mockup (a low detailed user-interface prototype). The paper focuses on Test Description Language, a notation used to store test cases
A WORKFLOW-ORIENTED APPROACH TO PROPAGATION MODELS IN HELIOPHYSICS
Get PDFThe Sun is responsible for the eruption of billions of tons of plasma andthe generation of near light-speed particles that propagate throughout the solarsystem and beyond. If directed towards Earth, these events can be damaging toour tecnological infrastructure. Hence there is an effort to understand the causeof the eruptive events and how they propagate from Sun to Earth. However, thephysics governing their propagation is not well understood, so there is a need todevelop a theoretical description of their propagation, known as a PropagationModel, in order to predict when they may impact Earth. It is often difficultto define a single propagation model that correctly describes the physics ofsolar eruptive events, and even more difficult to implement models capable ofcatering for all these complexities and to validate them using real observational data.In this paper, we envisage that workflows offer both a theoretical andpractical framerwork for a novel approach to propagation models. We definea mathematical framework that aims at encompassing the different modalitieswith which workflows can be used, and provide a set of generic building blockswritten in the TAVERNA workflow language that users can use to build theirown propagation models. Finally we test both the theoretical model and thecomposite building blocks of the workflow with a real Science Use Case that wasdiscussed during the 4th CDAW (Coordinated Data Analysis Workshop) eventheld by the HELIO project. We show that generic workflow building blocks canbe used to construct a propagation model that succesfully describes the transitof solar eruptive events toward Earth and predict a correct Earth-impact tim
VISIBILITY DETERMINATION IN BEAM TRACING WITH APPLICATION TO REAL-TIME SOUND SIMULATION
Get PDFThe work presents some aspects of beam tracing technique used in sound simulation. Adaptive Frustum algorithm, which was designed for detecting obstacles via beam subdivision was reviewed from efficiency point of view as well asfor its accuracy. Some possible improvements are suggested, however, they donot fully solve the problems of using this algorithm in real-time applications.Improved algorithm implementation was tested on five scenes with differentcharacteristics and varying complexity