An Approach Towards The Development Of An Efficient Symmetric Key Encryption Scheme

n the recent years protection of information in digital form is becoming more important. Image and video encryption has applications in various fields including Internet communications, multimedia systems, medical imaging, Tele-medicine and military communications. During storage as well as in transmission, the multimedia information is being exposed to unauthorized entities unless otherwise adequate security measures are built around the information system. There are many kinds of security threats during the transmission of vital classified information through insecure communication channels. Various encryption schemes are available today to deal with information security issues. Data encryption is widely used to protect sensitive data against the security threat in the form of “attack on confidentiality”. Secure transmission of information through insecure communication channels also requires encryption at the sending side and decryption at the receiving side. Encryption of large text message and image takes time before they can be transmitted, causing considerable delay in successive transmission of information in real-time. In order to minimize the latency, efficient encryption algorithms are needed. An encryption procedure with adequate security and high throughput is sought in multimedia encryption applications. Traditional symmetric key block ciphers like Data Encryption Standard (DES), Advanced Encryption Standard (AES) and Escrowed Encryption Standard (EES) are not efficient when the data size is large. With the availability of fast computing tools and communication networks at relatively lower costs today, these encryption standards appear to be not as fast as one would like. High throughput encryption and decryption are becoming increasingly important in the area of high-speed networking. Fast encryption algorithms are needed in these days for high-speed secure communication of multimedia data. It has been shown that public key algorithms are not a substitute for symmetric-key algorithms. Public key algorithms are slow, whereas symmetric key algorithms generally run much faster. Also, public key systems are vulnerable to chosen plaintext attack. In this research work, a fast symmetric key encryption scheme, entitled “Matrix Array Symmetric Key (MASK) encryption” based on matrix and array manipulations has been conceived and developed. Fast conversion has been achieved with the use of matrix table look-up substitution, array based transposition and circular shift operations that are performed in the algorithm. MASK encryption is a new concept in symmetric key cryptography. It employs matrix and array manipulation technique using secret information and data values. It is a block cipher operated on plain text message (or image) blocks of 128 bits using a secret key of size 128 bits producing cipher text message (or cipher image) blocks of the same size. This cipher has two advantages over traditional ciphers. First, the encryption and decryption procedures are much simpler, and consequently, much faster. Second, the key avalanche effect produced in the ciphertext output is better than that of AES.

Akzeptanz und Motivation beim selbstregulierten Lernen unter Einsatz von neuen Medien in der berufsbegleitenden Weiterbildung

Das Ziel der Dissertation war die Untersuchung des Computereinsatzes zur Lern- und Betreuungsunterstützung beim selbstgesteuerten Lernen in der Weiterbildung. In einem bisher konventionell durchgeführten Selbstlernkurs eines berufsbegleitenden Studiengangs, der an das Datenmanagement der Bürodatenverarbeitung heranführt, wurden die Kursunterlagen digitalisiert, die Betreuung auf eine online-basierte Lernbegleitung umgestellt und ein auf die neuen Lernmedien abgestimmtes Lernkonzept entwickelt. Dieses neue Lernkonzept wurde hinsichtlich der Motivation und der Akzeptanz von digitalen Lernmedien evaluiert. Die Evaluation bestand aus zwei Teilen: 1. eine formative, den Entwicklungsprozess begleitende Evaluation zur Optimierung der entwickelten Lernsoftware und des eingeführten Lernkonzeptes, 2. eine sowohl qualitative wie quantitative summative Evaluation der Entwicklungen. Ein zentraler Aspekt der Untersuchung war die freie Wahl der Lernmedien (multimediale Lernsoftware oder konventionelles Begleitbuch) und der Kommunikationsmedien (online-basierte Lernplattform oder die bisher genutzten Kommunikationskanäle: E-Mail, Telefon und Präsenztreffen). Diese Zweigleisigkeit erlaubte eine differenzierte Gegenüberstellung von konventionellen und innovativen Lernarrangements. Die Verbindung von qualitativen und quantitativen Vorgehensweisen, auf Grund derer die subjektiven Einstellungen der Probanden in das Zentrum der Betrachtung rückten, ließen einen Blickwinkel auf den Nutzen und die Wirkung der Neuen Medien in Lernprozessen zu, der es erlaubte einige in der Literatur als gängig angesehene Interpretationen in Frage zu stellen und neu zu diskutieren. So konnten durch eine Kategorisierung des Teilnehmerverhaltens nach online-typisch und nicht online-typisch die Ursache-Wirkungs-Beziehungen der in vielen Untersuchungen angeführten Störungen in Online-Seminaren verdeutlicht werden. In den untersuchten Kursen zeigte sich beispielsweise keine Abhängigkeit der Drop-out-Quote von den Lern- und Betreuungsformen und dass diese Quote mit dem neuen Lernkonzept nur geringfügig beeinflusst werden konnte. Die freie Wahl der Lernmedien führte zu einer gezielten Nutzung der multimedialen Lernsoftware, wodurch die Akzeptanz dieses Lernmedium stieg. Dagegen war die Akzeptanz der Lernenden gegenüber der Lernbegleitung mittels einer Online-Lernplattform von hoch bis sehr niedrig breit gestreut. Unabhängig davon reichte in allen Kursdurchgängen die Online-Betreuung nicht aus, so dass Präsenztreffen erbeten wurde. Hinsichtlich der Motivation war die Wirkung der digitalen Medien niedriger als erwartet. Insgesamt bieten die Ergebnisse Empfehlungen für die Planung und Durchführung von computerunterstützten, online-begleiteten Kursen.

Influence of education levels on dissemination of soil fertility management information in the central highlands of Kenya

Inadequate links between researchers and farmers has resulted in low uptake of research advances recommended to improve food security in the central highlands of Kenya. Access to timely and accurate information by extension agents and farmers is paramount in dissemination of soil fertility management practices. Hence, the study sought to investigate the effect of education levels on communication channels used to disseminate soil fertility technologies in the Central highlands of Kenya. Questionnaires were used to elicit information from 105 extension agents and 240 farmers. About 50.5% of the extension officers were certificate holders while 29.5% were diploma holders from agricultural institutes. Majority of the farmers had attained primary education (59.6%) while 25.8% and 9.2% had attained secondary and post secondary education, respectively. Research institutions were the most accessible sources of information on soil fertility management practices by extension agents while internet and scientific conferences were the least scored as accessible sources of soil fertility management information by extension agents. Education levels significantly influenced preference of individual approach methods by farmers. There was a significant positive relationship between education and accessibility of internet as a source of information on green manure. The implication of the study was that education levels influenced the mode of communication used in the transfer of soil fertility research outputs to the end users. Consequently, it is extremely important to consider education levels in selection of dissemination pathways used in agriculture.

El papel de las organizaciones Internacionales en la imagen de los Estados en el escenario internacional: La crisis Financiera de Argentina y la actuación del Fondo Monetario Internacional 2000- 2010

El presente trabajo de investigación tiene como objetivo identificar el papel que tuvo el Fondo Monetario Internacional [FMI] en el cambio de la imagen del Estado argentino después de la crisis financiera que estalló en el 2001. Como consecuencia de la declaración de default por parte del gobierno argentino se da un cambio en la imagen financiera del país, influenciada por el FMI, que convierte a Argentina en un paria internacional en temas financieros y comerciales alejándolo de los mercados internacionales. Este estudio de caso tendrá un acercamiento cualitativo dado que se analizarán las características, actuaciones y las bases crean el lazo entre las variables de la crisis financiera y el rol del FMI en Argentina y así poder entender su relación.

‘In the air’ and below the horizon: migrant workers in UK construction and the practice-based nature of learning and communicating OHS

Local, tacit and normally unspoken OHS (occupational health and safety) knowledge and practices can too easily be excluded from or remain below the industry horizon of notice, meaning that they remain unaccounted for in formal OHS policy and practice. In this article we stress the need to more systematically and routinely tap into these otherwise ‘hidden’ communication channels, which are central to how everyday safe working practices are achieved. To demonstrate this approach this paper will draw on our ethnographic research with a gang of migrant curtain wall installers on a large office development project in the north of England. In doing so we reflect on the practice-based nature of learning and sharing OHS knowledge through examples of how workers’ own patterns of successful communication help avoid health and safety problems. These understandings, we argue, can be advanced as a basis for the development of improved OHS measures, and of organizational knowing and learning.

Improving transmission reliability of low-power medium access control protocols using average diversity combining

Embedded computer systems equipped with wireless communication transceivers are nowadays used in a vast number of application scenarios. Energy consumption is important in many of these scenarios, as systems are battery operated and long maintenance-free operation is required. To achieve this goal, embedded systems employ low-power communication transceivers and protocols. However, currently used protocols cannot operate efficiently when communication channels are highly erroneous. In this study, we show how average diversity combining (ADC) can be used in state-of-the-art low-power communication protocols. This novel approach improves transmission reliability and in consequence energy consumption and transmission latency in the presence of erroneous channels. Using a testbed, we show that highly erroneous channels are indeed a common occurrence in situations, where low-power systems are used and we demonstrate that ADC improves low-power communication dramatically.

Networks and plant disease management: concepts and applications

A network is a natural structure with which to describe many aspects of a plant pathosystem. The article seeks to set out in a nonmathematical way some of the network concepts that promise to be useful in managing plant disease. The field has been stimulated by developments designed to help understand and manage animal and human disease, as well as by technical infrastructures, such as the internet. It overlaps partly with landscape ecology. The study of networks has helped identify likely ways to reduce flow of disease in traded plants, to find the best sites to monitor as warning sites for annually reinvading disease, and to understand the fundamentals of how a pathogen spreads in different structures. A tension between the free flow of goods or species down communication channels and free flow of pathogens down the same pathways is highlighted.

Controle da gestão pública e participação cidadã: a experiência da ouvidoria do Tribunal de Contas de Pernambuco

Dentre os diversos temas de interesse social, a pesquisa realizada enfocou as relações entre Estado e sociedade, destacando a função de controle sobre a improbidade administrativa como instrumento relevante para o aprimoramento da gestão pública e para a melhoria das condições de vida da população. A investigação destacou a atuação do Tribunal de Contas de Pernambuco, as formas de controle institucional e o modo como o cidadão exerce o controle social da Administração Pública. Os resultados dos estudos, baseados na revisão da literatura sobre o tema e na experiência do Tribunal, apontam caminhos para a participação social e indicam a necessidade de constante reflexão sobre a prática institucional. A pesquisa compreendeu a identificação dos canais de comunicação estabelecidos entre o TCE-PE e a sociedade, por meio dos programas da Escola de Contas Públicas Barreto Guimarães e particularmente da Ouvidoria. O trabalho ressaltou o encaminhamento dado pelo Tribunal às denúncias de irregularidades encaminhadas pelo cidadão à Ouvidora. A análise das denúncias e a repercussão da participação do cidadão foram observadas nos julgamentos dos processos oriundos de demandas da Ouvidoria. O estudo ofereceu uma visão geral da organização e do funcionamento do Tribunal de Contas de Pernambuco e sua relação com a sociedade, em busca de um controle mais efetivo da improbidade administrativa. Tendo em vista a novidade da investigação no âmbito dos Tribunais de Contas, a abordagem utilizada revestiu-se de caráter exploratório.

The market strategies alternatives of an e-business start-up in Brazil

The e-business market is one of the fastest growing markets in Brazil, with e-business sales accounting for BRL 14.8 billion in 2010 and a growth of 40% per year (+1000% over the past 7 years). Sales-event clubs and collective bargaining websites are one of the most dynamic segments of the e-business market: the number of new players is increasing rapidly, with over 1200 collective bargaining websites currently operating in Brazil. In that context, growth and differentiation seem to be two key success factors for Coquelux. According to webshopper (23rd Edition, e-bit), growth can be achieved by targeting middle and low-income consumers from class C, who represent 50% of the total e-commerce sales. But Coquelux, which is specialized in desire and luxury brands, has built its reputation and competitive advantage through its “exclusivity”, by targeting wealthier consumers from classes A and B who are attracted by its fashionable and high-end positioning. The evolution (growth?) of this market and the development of its competition naturally raise a strategic question for Coquelux’s managers: can Coquelux grow and still maintain its competitive advantage? Should it grow by expanding its consumer base to class C? If so, how? Consumers from classes A, B or C must be targeted through the same online communication channels. Recent studies from the ABEP/ABIPEME emphasized the importance of social networks as a tool for converting new clients and gaining their loyalty, regardless of their social class. However, high-income and low-income e-consumers do not have the same consumption habits, do not respond to the same type of marketing strategies, and most importantly, do not share the same values. Thus, it seems difficult to expand Coquelux’s consumer base to class C without changing its marketing strategies and altering its image Three options were identified for Coquelux: reinforcing its leadership on the luxury segment and focusing on a small niche market (1), which would threaten its survival in the long run; completely changing its strategy and competing for a mass market through commercial brands (2), which requires major financial investments that managers don’t have access to; or finding an intermediary solution (3). This thesis’ recommendation for the third option consists in focusing on premium brands (rather than luxury) in order to increase sales volume (Coquelux’s most profitable sales happened with local desire brands) with products that appeal to class B but also attract the emerging class C which is looking for brand recognition. It could thus implement a slow entry strategy towards the mass market without damaging its main competitive advantage.

“O sindicato que a ditadura queria”: o Ministério do Trabalho no governo Castelo Branco (1964-1967)

Esse trabalho tenta analisar a atuação do Ministério do Trabalho através da articulação de seus ministros com outras áreas da burocracia estatal, durante o governo Castelo Branco, para, por um lado, reprimir e expurgar opiniões contrárias ao regime ditatorial e, por outro, promover uma nova política para os trabalhadores, o “novo trabalhismo”. O termo condensava a ideia da área econômica de ‘democratizar’ as oportunidades, ampliando as atribuições dos sindicatos, deslocando o seu foco das reivindicações salariais para o desenvolvimento, em associação com o governo, de projetos e programas de investimentos nos setores sociais de produtividade indireta. Para implementar a proposta, cada ministro teve que lidar com as pressões advindas do processo de alteração da política trabalhista e articular os seus interesses pessoais com as atribuições da pasta. Arnaldo Sussekind resistiu às demandas para o fim da estabilidade, alterou a Lei de Greve, permitiu o fracionamento do 13º salário e abriu espaço para a implantação da política salarial. Ao mesmo tempo promoveu uma massiva intervenção nos sindicatos, cujos processos permitem conhecer melhor o interior da burocracia estatal, perceber os argumentos utilizados para afastar as diretorias das entidades e questionar a tomada de decisões dentro do ministério sob o novo contexto social pós-golpe. Walter Peracchi Barcelos utilizou a pasta como trampolim político, propondo e executando ações repressivas que lhe garantiam vantagens políticas e negligenciando projetos da área econômica, como o Fundo de Garantia por Tempo de Serviço, que ameaçavam importantes conquistas dos trabalhadores. Por fim, Luiz Gonzaga do Nascimento e Silva reformulou o Banco Nacional da Habitação e unificou a previdência, ações que permitiram a transferência de atribuições e recursos do Estado para a iniciativa privada. A pesquisa, portanto, sustenta que o Ministério do Trabalho, após o golpe, perdeu poder político dentro do governo por permitir a transferência de suas atribuições para camadas da elite empresarial e para os militares, forçando os sindicatos a modificarem seus canais de diálogo e suas reivindicações para se adaptarem ao novo contexto.

An online platform for real-time sensor data collection, visualization, and sharing

Sharing sensor data between multiple devices and users can be^challenging for naive users, and requires knowledge of programming and use of different communication channels and/or development tools, leading to non uniform solutions. This thesis proposes a system that allows users to access sensors, share sensor data and manage sensors. With this system we intent to manage devices, share sensor data, compare sensor data, and set policies to act based on rules. This thesis presents the design and implementation of the system, as well as three case studies of its use.

A comunicação interna numa organização pública

The present study compose an analysis on the process of internal communication at a public organization, built on the survey data originary of administrative conduct, observation on the cultural model of the organization and how the interdepartmental and interpersonal relations shows up. The research, exploratory descriptive kind, had theoretical basis on two knowledge areas Administrative Science and Social Communication and was developed at Instituto do Desenvolvimento Econômico e Meio Ambiente IDEMA, in Rio Grande do Norte. During data collection, were conducted spontaneous and semi structured interviews with directors and coordinators, besides the application of directed questionnaire to functionaries in two unites of the institution. Through the analysis and interpretation of the data, we came to the conclusion that the process of internal communication at a public organization fall in with same challenges of private organizations, but with peculiarities that attracts the scientific look specially, in concern of the attitude assumed by the administrators in the conduction of communication functions inside the organization, the profile of social actor and the communication channels used. Although the organizational communication represents more and more a strategic function, as an administration tool, the point that research gets to shows that in public organizations the communication refrains from administrative purpose and with the major objective of giving publicity to the institutional acts and actions

Simulation and analysis of a collisionless optical interconnection network

This article describes the simulation and analysis of collisionless optical interconnection network, which the objective is to achieve a high performance level based on a single protocol control. The optical coupler has one shared control channel and N communication channels. Each network node two communication modules one for packet transmission/reception and another for control channel access. We show by simulation that system achieves a high performance and ensures high scalability.

ExperimentAR-TE: as oficinas de recursos expressivos em uma casa abrigo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aspectos relativísticos da teoria da informação quântica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)