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Search Results: 1 - 10 of 3699 matches for " Joshua Zukewich "
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Consolidating Birth-Death and Death-Birth Processes in Structured Populations
Joshua Zukewich, Venu Kurella, Michael Doebeli, Christoph Hauert
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054639
Abstract: Network models extend evolutionary game theory to settings with spatial or social structure and have provided key insights on the mechanisms underlying the evolution of cooperation. However, network models have also proven sensitive to seemingly small details of the model architecture. Here we investigate two popular biologically motivated models of evolution in finite populations: Death-Birth (DB) and Birth-Death (BD) processes. In both cases reproduction is proportional to fitness and death is random; the only difference is the order of the two events at each time step. Although superficially similar, under DB cooperation may be favoured in structured populations, while under BD it never is. This is especially troubling as natural populations do not follow a strict one birth then one death regimen (or vice versa); such constraints are introduced to make models more tractable. Whether structure can promote the evolution of cooperation should not hinge on a simplifying assumption. Here, we propose a mixed rule where in each time step DB is used with probability and BD is used with probability . We derive the conditions for selection favouring cooperation under the mixed rule for all social dilemmas. We find that the only qualitatively different outcome occurs when using just BD (). This case admits a natural interpretation in terms of kin competition counterbalancing the effect of kin selection. Finally we show that, for any mixed BD-DB update and under weak selection, cooperation is never inhibited by population structure for any social dilemma, including the Snowdrift Game.
Do Ghanaians Prefer Imported Textiles to Locally Manufactured Ones?  [PDF]
Peter Quartey, Joshua Abor
Modern Economy (ME) , 2011, DOI: 10.4236/me.2011.21009
Abstract: This paper ascertains whether consumers prefer locally made textile to imported ones or vice versa and what accounts for the choice. The study uses survey data of industry, traders and consumers to explain the issue. The results show that most consumers prefer locally-made textiles to imported ones. More than half of those who prefer locally-made textiles claimed local textile products are of a better quality. Others claimed they are more affordable and attractive while a few claimed local textiles are cheaper. This appears to contradict the country-of-origin effect and the results of previous studies in Africa and other developing countries. Im-plications for traders, governments and local manufacturers are also discussed. The study provides insights with respect to Ghanaians’ preference of locally-produced textiles to foreign-made ones.
Providing Sustainable Supports for Street Children in Nigeria:Stakeholders Challenges and the Policy Options Available  [PDF]
Joshua Oyeniyi Aransiola
Advances in Applied Sociology (AASoci) , 2013, DOI: 10.4236/aasoci.2013.33023

This article examines the limitations of all stakeholders in providing support for street children in Nigeria in the face of continuous increase in their number with a view to identify possible policy options in the light of inabilities of the stakeholders to adequately support the children. Qualitative research techniques were employed to collect the primary data from NGOs, community members and government agencies saddled with the responsibility of caring for the children. It was found that the stakeholders are incapable of addressing the problems of street children due to inadequate skills, lack of necessary facilities and stakeholders working in parallels among others. It emphasizes the need for collaboration among stakeholders to enjoy the benefit of synergy while there is also need to embark on capacity development for all the stakeholders in order to make meaningful progress and the situation of the street children improved in the country.

A Reconfigurable Network-on-Chip Datapath for Application Specific Computing  [PDF]
Joshua Weber, Erdal Oruklu
Circuits and Systems (CS) , 2013, DOI: 10.4236/cs.2013.42025

This paper introduces a new datapath architecture for reconfigurable processors. The proposed datapath is based on Network-on-Chip approach and facilitates tight coupling of all functional units. Reconfigurable functional elements can be dynamically allocated for application specific optimizations, enabling polymorphic computing. Using a modified network simulator, performance of several NoC topologies and parameters are investigated with standard benchmark programs, including fine grain and coarse grain computations. Simulation results highlight the flexibility and scalability of the proposed polymorphic NoC processor for a wide range of application domains.

Refining Use/Misuse/Mitigation Use Cases for Security Requirements  [PDF]
Joshua J. Pauli
Journal of Software Engineering and Applications (JSEA) , 2014, DOI: 10.4236/jsea.2014.78058

We investigate security at the same time as the functional requirements by refining and integrating use, misuse, and mitigation use cases. Security requirements rely on the interactions among normal system execution (use cases), attacks (misuse cases), and necessary security strategies (mitigation use cases), but previous approaches only use a high-level of abstraction. We use refinement to uncover details of each case and the relationships among them before integrating them. We identify and model “includes” and “extends” relationships within each refined case type, and use a condition-driven process that maintains these relationships as refinement continues. We then systematically identify and model “threatens” and “mitigates” relationships to integrate the cases at a detailed level.

Establishing a Different Dimension of Citizen Security: The Case for Special Protection for Whistleblowers  [PDF]
David Lewis, Joshua Castellino
Beijing Law Review (BLR) , 2013, DOI: 10.4236/blr.2013.44024

The notion of citizens’ security has usually been viewed primarily as a binary relationship between the State and the citizen in a Rousseauesque interpretation. This article argues for a broader conception of citizens’ security focussing on the right to “blow the whistle” in an employment context. We believe that with the growing importance of global business in society it is imperative that special measures are designed for this important class of citizens. A failure to do so, in our opinion, is likely to harm the maintenance of effective protection, especially in developing countries, to the detriment of citizens’ security.

Perceptions and Use of Herbal Remedies among Patients with Diabetes Mellitus in Murang’a North District, Kenya  [PDF]
Joshua Mwangi, Lucy Gitonga
Open Journal of Clinical Diagnostics (OJCD) , 2014, DOI: 10.4236/ojcd.2014.43024
Abstract: Diabetes mellitus is a chronic disease with a world wide distribution. Use of herbal remedies has been on increase with World Health Organization estimating that 80 percent of the world’s population presently uses some form of herbal medicine for some aspect of primary health care. Objectives of this study were therefore to determine the perceptions people with diabetes mellitus have towards herbal remedies, to determine the extent to which they use herbal remedies and also to establish whether there is any association between the perceptions people have on herbal remedies and use of herbal remedies. The study was carried out in Murang’a District, in Mathioya and Kangema Constituencies where five community health units were purposively selected to participate in the study based on their level of establishment in community health strategy. Data was collected using interview schedules. SPSS was used for data analysis. Significant findings from this study were: a significant number of the respondents (15%) were diagnosed with diabetes mellitus when already admitted in the wards prior to which period they had no idea that they were diabetic, over 86% of those interviewed were given information on diabetes management on diagnosis and they attend hospital clinics for follow-up regularly and therefore this means that the reason for seeking alternative modes of treatment is not due to lack of information on diabetes but due to other reasons, 12.4% of those interviewed admitted using herbal remedies as part of their management of diabetes. Recommendations made following the study were: the government of Kenya through Ministry of Health should encourage rigorous screening of clients and population in general for diabetes to ensure diabetes is diagnosed early and put under appropriate management and that the government of Kenya through Ministry of Health should put up a campaign educating diabetic patients on the potential dangers associated with combining herbal remedies with contemporary medicines due to their interactions.
Quantifying the Value of Open Source Hard-ware Development  [PDF]
Joshua M. Pearce
Modern Economy (ME) , 2015, DOI: 10.4236/me.2015.61001
Abstract: With the maturation of digital manufacturing technologies like 3-D printing, a new paradigm is emerging of distributed manufacturing in both scientific equipment and consumer goods. Hardware released under free licenses is known as free and open source hardware (FOSH). The availability of these FOSH designs has a large value to those with access to digital manufacturing methods and particularly for scientists with needs for highly-customized low-volume production products. It is challenging to use traditional funding models to support the necessary investment of resources in FOSH development because of the difficulty in quantifying the value of the result. In order to overcome that challenge and harvest the current opportunity in both low-cost scientific equipment and consumer products, this article evaluates the following methods to quantify the value of FOSH design including: 1) downloaded substitution valuation; 2) avoided reproduction valuation and 3) market savings valuation along with additional benefits related to market expansion, scientific innovation acceleration, educational enhancement and medical care improvement. The strengths and weaknesses of these methods are analyzed and the results show that the methods are relatively straight-forward to institute, based on reliable freely-available data, and that they minimize assumptions. A case study of a syringe pump with numerous scientific and medical applications is presented. The results found millions of dollars of economic value from a relatively simple scientific device being released under open-licenses representing orders of magnitude increase in value from conventional proprietary development. The inescapable conclusion of this study is that FOSH development should be funded by organizations interested in maximizing return on public investments particularly in technologies associated with science, medicine and education.
The Effect of Lion’s Ear (Leonotis nepetifolia) and African Basil (Ocimum gratissimum) Plant Extracts on Two-Spotted Spider Mites (Tetranychus urticae) for Improved Yield and Quality of French Beans  [PDF]
Kennedy Ogayo, Jane Nyaanga, Joshua Ogweno, Joshua Ogendo
Advances in Entomology (AE) , 2019, DOI: 10.4236/ae.2019.71003
Abstract: An experiment to evaluate the bio-control potential of Leonotis nepetifolia and Ocimum gratissimum plant extracts against two-spotted spider mites on French beans was conducted in the field. Five plant extract concentrations (1.5%, 3.0%, 6.0% and 12.0% w/v) were applied with water and Abamectin 0.6 ml/L as controls. Mite counts were done before and after treatment application and expressed as corrected percent efficacy. The impact of the mites on the French beans was evaluated by recording percent leaf reduction and quality and quantity by number of pods, pod length, diameter and yield. There was a dose dependent response in percent mite and leaf reduction, number of pods and yield. Treatments applied at 12% w/v indicated higher mite reduction (82.75%) for L. nepetifolia and 69.06% for O. gratissimum compared to abamectin (65.76%). The lowest percent leaf reduction of 1.71% for L. nepetifolia 0.39% for O. gratissimum and abamectin (20.46%) was also at 12% w/v. Similarly, the highest number of pod (61.00) for L. nepetifolia, 48.67 for O. gratissimum compared to 28.33 abamectin and yield (0.88 kg) for L. nepetifolia and 0.90 kg for O. gratissimum was also recorded at 12% w/v compared to 0.36 kg for abamectin. There were no significant differences in pod diameter and pod length between the extracts concentrations and abamectin. The study demonstrated the efficacy of L. nepetifolia and O. gratissimum in managing two-spotted spider mite and subsequent increase in French bean yield under field conditions.
Control of an Industrial SCR Catalyst Using Ceramic NOx Sensors  [PDF]
Joshua Schmitt, Daniel B. Olsen
Energy and Power Engineering (EPE) , 2011, DOI: 10.4236/epe.2011.33039
Abstract: Selective Catalytic Reduction (SCR) catalysts respond slowly to transient inputs, which is troublesome when designing ammonia feed controllers. An experimental SCR test apparatus installed on a slipstream of a Coo-per-Bessemer GMV-4, 2-stroke cycle natural gas engine is utilized. Ammonia (NH3) feed rate control algo-rithm development is carried out. Two control algorithms are evaluated: a feed forward control algorithm, using a pre ammonia injection ceramic NOx sensor and a feed forward plus feedback control algorithm, us-ing a pre ammonia injection ceramic NOx sensor and post catalyst ceramic NOx sensor to generate feedback signals. The feed forward algorithm controls to constant user input NH3/NOx molar ratio. The data show the lack of pressure compensation on the ceramic NOx sensors cause errors in feed forward NOx readings, re-sulting in sub optimal ammonia feed. The feedback system minimizes the post catalyst ceramic NOx sensor signal by adjusting the NH3/NOx molar ratio. The NOx sensors respond to ammonia + NOx; therefore, the feed forward plus feedback algorithm minimizes the sum of NOx emissions and ammonia slip. Successful application of the feedback control minimization technique is demonstrated with feedback periods of 15 and 5 minutes with molar ratio step sizes of 5 and 2.5%, respectively.
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