ENKRIPSI DESKRIPSI DENGAN METODE VIGENERE CIPHER, XOR DAN KOMPRESI HUFFMAN UNTUK KERAHASIAAN SMS BERBASIS ANDROID

Perkembangan yang cukup signifikan pada teknologi, salah satunya adalah telepon selular (ponsel) yaitu yang sekarang dikenal luas adalah smartphone android. Teknologi sms pada smartphone android membuka kesempatan untuk mengembangkan aplikasi sms menuju arah baru salah satunya adalah aplikasi sms enkripsi dan kompresi. Pada aplikasi ini memungkinkan user mengirim sms dengan tingkat kerahasiaan yang cukup untuk mengamankan pesan yang bersifat pribadi agar tidak dapat diakses oleh pihak lain. Pengujian aplikasi pada ponsel android berjalan dengan baik yaitu pengiriman pesan dapat dilakukan dengan baik dan proses enkripsi dan kompresi pada aplikasi ini juga berjalan dengan baik. Aplikasi ini akan dibuat menggunakan bahasa pemrograman java dengan platform android yang terdapat pada Eclipse. Kesimpulan yang dicapai adalah bahwa aplikasi sms enkripsi dan kompresi pada ponsel android dapat diwujudkan. Kata kunci : Android, Enkripsi, Kompresi, Smartphone, Sms

RELATIONSHIP BETWEEN CHEMISTRY LABORATORY WORK AND STUDENTS’ ACADEMIC PERFORMANCE IN CHEMISTRY, IN KILIFI NORTH CONSTITUENCY, KENYA

Despite the fact that Chemistry is the gatekeeper and backbone of other science subjects, the general performance in Chemistry among secondary school students countrywide remains poor. Research evidence shows that poor performance in Chemistry not only results from intrinsic conceptual difficulties in the subject but also springs from poor Chemistry Laboratory work. However, Chemistry educationists seem to be in disagreement with respect to the relationship between Chemistry Laboratory work and students’ academic performance in Chemistry. This study, therefore, sought to find out the relationship between Chemistry Laboratory work and students’ academic performance in Chemistry. The study was guided by John Dewey’s Constructivist Learning theory. The study was conducted in Kilifi North Constituency. The research design was correlation, simple random sampling was used to select one girl school, six mixed schools, and Purposive sampling was used to select one boys’ school. Stratified random sampling and simple random sampling were used to select 80 students. Data was collected by use of Student Questionnaire (SQ) and through analysis of documents and mark sheet form. Statistical package for social sciences (SPSS) was used to facilitate data analysis. Descriptive statistics and inferential statistics were used. The level of significant used in the study was 0.05. The findings revealed, 27.5% of schools utilize the expected 11-13 lessons per term, 33.75% utilizes 7-10 lessons and 38.75% utilizes 3-6 lessons. The findings emerging from this study also revealed that there was a significant positive relationship between; the use of chemistry laboratory and student’s academic performance in chemistry. In conclusion, students whose teachers always take them to the laboratory during practical lessons performed better in practical examinations.  Article visualizations

INFLUENCE OF SOCIAL MEDIA ON KNOWLEDGE SHARING PRACTICES IN KENYAN UNIVERSITIES: A CASE OF STRATHMORE UNIVERSITY

The main objective of the research was to reveal the influence of social media tools on the sharing of knowledge in Kenyan universities. The research population was arrived at and evaluated using purposive sampling, while data was gathered using questionnaires. The study further adopted descriptive research design with a statistical sample of 233 students from the Faculty of Information Technology at Strathmore University. Statistical Package for the Social Sciences (SPSS) version 21 was the software used to analyse the gathered data. Descriptive statistics (percentage and frequency) were used to present as well as deduce the major findings for the research. Inferential statistics comprising correlation, multiple linear regression models and ANOVA analysis were used to find out the connection between the dependent and independent variables. Results of the study revealed that the four constructs namely social media determinants, user perceptions, social media tools and social media barriers have a significant influence on knowledge sharing in Kenyan universities. The findings further depicted that the studied social media tools (Facebook, WhatsApp, Twitter, and blogs) resulted in better communication, collaboration, interaction and knowledge sharing amongst the students in Kenyan universities, and hence generally improved knowledge sharing. The ANOVA results revealed that social media had a significant influence on knowledge sharing. The study concluded that social media contributed immensely to knowledge sharing in one way or another amongst university students in Kenya. The study therefore recommended that Kenyan universities enhanced social media use for knowledge sharing through adopting social media as substitute to official communication, drafting comprehensive social media policies which include sections on knowledge sharing, ensuring security and controls over information shared via social media, facilitating students to have portable gadgets such as smartphone, laptops among others, and finally introducing units on social media in their curriculum

All manganite tunnel junctions with interface induced barrier magnetism

El texto completo de este trabajo no se encuentra disponible por no haber sido facilitado aún por su autor, por restricciones de copyright, o por no existir una versión digital Artículo firmado por 18 autoresIn epitaxial heterostructures combining strongly correlated manganese oxides with antiferromagnetic-insulator or half-metallic character, a large interfacial moment is found and used to produce a spin-filter-like behavior in all-manganite tunnel junctions. The results suggest that after playing a key role in exchange-bias for spin-valves, uncompensated moments at engineered antiferromagnetic interfaces represent a novel route for generating highly spin-polarized currents with antiferromagnets.Ministerio de Ciencia y EducaciónPrograma Ramon y CajalCAM under PHAMARéseau Thématique de Recherche Avancée “Triangle de la Physique”Depto. de Física de MaterialesFac. de Ciencias FísicasTRUEpu