Hardware Implementation of Efficient Elliptic Curve Scalar Multiplication using Vedic Multiplier

This paper presents an area efficient and high-speed FPGA implementation of scalar multiplication using a Vedic multiplier. Scalar multiplication is the most important operation in Elliptic Curve Cryptography(ECC), which used for public key generation and the performance of ECC greatly depends on it. The scalar multiplication is multiplying integer k with scalar P to compute  Q=kP, where k is private key and P is a base point on the Elliptic curve. The Scalar multiplication underlying finite field arithmetic operation i.e. addition multiplication, squaring and inversion to compute Q. From these finite field operations, multiplication is the most time-consuming operation, occupy more device space and it dominates the speed of Scalar multiplication. This paper presents an efficient implementation of finite field multiplication using a Vedic multiplier.  The scalar multiplier is designed over Galois Binary field GF(2233) for field size=233-bit which is secured curve according to NIST.  The performances of the proposed design are evaluated by comparing it with  Karatsuba based scalar multiplier for area and delay. The results show that the proposed scalar multiplication using Vedic multiplier has consumed 22% less area on FPGA and also has 12% less delay, than Karatsuba, based scalar multiplier. The scalar multiplier is coded in Verilog HDL, synthesize and simulated in Xilinx 13.2 ISE on Virtex6 FPGA

The Role of Workers Militia in the Ethio-Somalia War,1977-78

The Somali irredentist aimed at establishing Greater Somalia by conquering all the Somali speaking areas in East Africa. In doing so, Somali invaded Ethiopia in 1964 and 1977/78 respectively. During the two invasions, the Ethiopian workers led by the Confederation of Ethiopian Labour Unions (CELU) and the All Ethiopian Trade Unions (AETU) defended the sovereignty of their country. More importantly, in the second Ethio-Somalia war, a number of Ethiopian workers were organized under two militia Brigades and three mixed Brigades and defended their country. This paper therefore attempts to reconstruct the role of the Ethiopian workers in defending the sovereignty of Ethiopia in the Ethio-Somalia war. Since this is a qualitative study, data for the study was collected through document analysis and in-depth interviews. The collected data were analyzed thematically. The findings show that the Ethiopian workers participated in the second Ethio-Somalia war not only as drivers and technicians of military convoys but also as militia combatants and defended their motherland from irredentists

The Formative Period of the Ethiopian Labour Movement, 1962-1974

As a result of internal and external factors, the imperial regime issued a labour relations decree, Decree No.49/1962 and recognized labour unions and employers' associations for the first time in the history of Ethiopian labour movement on 5 September 1962. This in turn resulted in the birth of the Confederation of Ethiopian Labour Union (CELU) on 9 April 1963 and the Ethiopian Employers' Federation (EEF) on 11 April 1964. In a nut shell, the years from 1962 to1974 can be taken as the formative years in the history of the Ethiopian labour movement. Therefore, this study tries to investigate the formative period of the Ethiopian labour movement in which workers sought to establish an independent labour union and undertaken stiff struggle to that end. As a qualitative research, the study used document analysis and in-depth interview to collect data. It also used thematic analysis to analyze the collected data. The findings of the study showed that the strong subordination of CELU to the state and the enduring internal power struggle among its leaders contributed a lot to the failure of the Ethiopian labour movement to establish an independent national confederation and to be an agent for the 1974 Ethiopian revolution

Electronic Transport and Switching Phenomena in Low-Dimensional Materials

This dissertation reports results of an investigation of electron transport in two classes of layered van der Waals materials: quasi-one-dimensional (1D) transition metal trichalcogenides (TMTs) and quasi-two-dimensional (2D) transition metal dichalcogenides (TMDs). Practical motivations for this study include the search for (i) materials, which can be used in ultimately downscaled interconnects in the next generations of electronics, and (ii) materials revealing low power switching phenomena, which can be used in future logic circuits. TMTs have strong covalent bonds in one direction and weaker bonds in cross-plane directions. They can be prepared as crystalline nanoribbons consisting of 1D atomic threads, i.e. chains. I have examined the current carrying capacity of ZrTe3 nanoribbons using structures fabricated by the shadow mask method. It was found that ZrTe3 nanoribbons reveal an exceptionally high current density, on the order of ~100 MA/cm2, at the peak of the stressing current. I have investigated the low-frequency electronic noise in such nanoribbons. The low-frequency noise data were used to determine the activation energy for electromigration. TMDs reveal interesting charge-density-wave (CDW) effects, which can be triggered by electric bias even at various temperatures. I investigated switching among three CDW phases – commensurate, nearly commensurate, incommensurate – and the normal metallic phase in 1T-TaS2 devices induced by application of an in-plane bias voltage. The switching among all phases was achieved over a wide temperature range, from 77 K to 400 K. The electronic noise spectroscopy was used as an effective tool for monitoring the transitions. The noise exhibits sharp increases at the phase transition points, which correspond to the step-like changes in resistivity. The possibility of the bias-voltage switching among four different phases of 1T-TaS2 is a promising step toward nanoscale device applications. The results also demonstrate the potential of noise spectroscopy for investigating and identifying phase transitions in the materials

LAMINAR-TURBULENT TRANSITION FLOWS OF NON-NEWTONIAN SLURRIES: MODELS ASSESSMENT

ABSTRACT In this study a qualitative assessment of transitional velocity engineering models for predicting non-Newtonian slurry flows in a horizontal pipe was performed using data from wide pipe diameters (25 -268 mm). In addition, Gamma Theta transition model was used to compute selected flow conditions. In general, it was observed that most of the current engineering models predict conservative transitional velocities. However, caution should be exercised in design situations where both pipe diameter and viscoplastic viscosity influence the value of Hedström number. It was found that the Gamma Theta transition model predicted a laminar flow condition in the fully developed region which is contrary to what has been observed in experiment

Pathogenicity and fungicide sensitivity of the causal agent of postharvest stem end rot disease of mango in Ghana

ABSTRACTStudies were carried out on the stem end rot disease of mango in Ghana. The incidence and severity of the disease were evaluated on mango fruits collected from major mango growing areas of Ghana. The causal agent was isolated on media and identified. The pathogenicity of the fungus and its cross-infection potential were determined on mango, avocado, papaya and banana fruits. The sensitivity of the pathogen to fungicides was determined by assessing radial mycelial growth on potato dextrose agar (PDA) amended with nine different fungicides (Bendazim, Funguran, Ivory, Topsin, Asuoku master, Kocide, Mirage, Sulphur 80 and Copper oxychloride). Stem end rot disease was prevalent in the major mango growing areas of Ghana. Two pathogens, Lasiodiplodia theobromae and Colletotrichum gloeosporioides were isolated from the disease lesions. However, only the former was able to cause stem end rot disease symptoms on the artificially inoculated fruits, confirming it as the causal agent of the disease. It was also found to be highly susceptible to Bendazim, Ivory, Topsin, Asuoku master and Mirage, whilst it was resistant to Funguran, Kocide, Sulphur 80 and Copper oxychloride.Original sciencitic paper. Received 30 Apr 15; revised 17 Oct 14

Prevalence and predictors of uterine rupture among Ethiopian women: A systematic review and meta-analysis.

BackgroundUterine rupture has a significant public health importance, contributing to 13% of maternal mortality and 74%-92% of perinatal mortality in Sub-Saharan Africa, and 36% of maternal mortality in Ethiopia. The prevalence and predictors of uterine rupture were highly variable and inconclusive across studies in the country. Therefore, this systematic review and meta-analysis aimed to estimate the pooled prevalence and predictor of uterine rupture in Ethiopia.MethodsThis systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 checklist. PubMed, Cochrane Library, Google Scholar, and African Journals Online databases were searched. The Newcastle- Ottawa quality assessment tool was used for critical appraisal. I2 statistic and Egger's tests were used to assess the heterogeneity and publication bias, respectively. The random-effects model was used to estimate the pooled prevalence and odds ratios with a 95% confidence interval.ResultsSixteen studies were included, with a total of 91,784 women in the meta-analysis. The pooled prevalence of uterine rupture was 2% (95% CI: 1.99, 3.01). The highest prevalence was observed in the Amhara regional state (5%) and the lowest was in Tigray region (1%). Previous cesarean delivery (OR = 9.95, 95% CI: 3.09, 32.0), lack of antenatal care visit (OR = 8.40, 95% CI: 4.5, 15.7), rural residence (OR = 4.75, 95% CI: 1.17, 19.3), grand multiparity (OR = 4.49, 95% CI: 2.83, 7.11) and obstructed labor (OR = 6.75, 95%CI: 1.92, 23.8) were predictors of uterine rupture.ConclusionUterine rupture is still high in Ethiopia. Therefore, proper auditing on the appropriateness of cesarean section and proper labor monitoring, improving antenatal care visit, and birth preparedness and complication readiness plan are needed. Moreover, early referral and family planning utilization are the recommended interventions to reduce the burden of uterine rupture among Ethiopia women

Novel approaches toward the development of an oral post-exposure DNA vaccine for latent tuberculosis using Salmonella typhimurium ΔaroA vector

Tuberculosis remains one of the major causes of global public health problems. There is no effective vaccine for the disease until now. Many reports show that DNA vaccines are promising to induce protection against Mycobacterium tuberculosis (M. tb); however, the efficiency of DNA vaccine is limited due to inadequate delivery systems. Among others, live attenuated bacterial vectors such as Salmonella enterica typhimurium (S. typhimurium) have significant promise as efficient mucosal delivery vehicles for DNA vaccines. In this study, we constructed recombinant attenuated S. typhimurium DNA vaccines carrying genes encoding resuscitation promoting factor (Rpf)-like proteins of M. tb on eukaryotic expression plasmid agianst latent tuberculosis and evaluated the plasmid stability and growth curve assays of the recombinant Salmonella vaccine constructs in vitro. Four Rpf gene fragments (RpfB, RpfC, RpfD, RpfE) associated with latency were amplified from genomic DNA of the H37Rv strain of M. tb, cloned into eukaryotic expression plasmid (pVR1020) and verified by sequencing. In later studies, we will demonstrate the potential use of the Salmonella-mediated DNA constructs as candidate post-exposure vaccines against tuberculosis through testing their immunogenicity and effectiveness for oral delivery in eukaryotic systems.Key words: Latent tuberculosis, resuscitation promoting factor (Rpf), DNA vaccine, recombinant Salmonella typhimurium