The First Generation of Computers

Author(s):  
Giuseppe Primiero

This chapter starts with the analysis of the engineering foundation of computing which, proceeding in parallelwith themathematical foundation, led to the design and creation of physical computingmachines. It illustrates the historical evolution of the first generation of computing and their technical foundation, known as the von Neumann architecture. Fromthe conceptual point of view, the chapter clarifies the relation between the universal model of computation and the construction of an all-purpose machine.

2021 ◽  
Vol 13 ◽  
pp. 184797902199450
Author(s):  
Reyner Pérez-Campdesuñer ◽  
Gelmar García-Vidal ◽  
Alexander Sánchez-Rodríguez ◽  
Rodobaldo Martínez-Vivar ◽  
Margarita de Miguel-Guzmán ◽  
...  

Entrepreneurship is an important part of any economy today regardless of its level of development. However, not in all contexts do entrepreneurs operate in the same way, nor are they motivated by the same factors. This research seeks to identify possible coincidence factors and differences between entrepreneurs that operate in different contexts from the point of view of their historical evolution, the duration of these and the economic and social model applied in the countries. Specifically, a comparative study is carried out between entrepreneurs from the republics of Ecuador and Cuba considering various variables such as: personality characteristics (attitude to failure, risk, perseverance and innovation), use of the available time fund for work in entrepreneurship; Impact of the environment in relation to: government regulations, taxes, level of competition and availability of suppliers, as well as the structure of personal expenses projected in the short and long term that entrepreneurs assume as a stimulus for their actions. For the development of the study, a description of the behavior of the variables was initially made and later, by hypothesis testing, to verify differences and similarities between both populations. The study allowed us to identify common and divergent aspects between both populations analyzed. Similarly, it showed how differences in the administrative and financial environment in which entrepreneurs operate generate changes in their priorities and projections.


1988 ◽  
Vol 53 (4) ◽  
pp. 1177-1187
Author(s):  
W. A. MacCaull

Using formally intuitionistic logic coupled with infinitary logic and the completeness theorem for coherent logic, we establish the validity, in Grothendieck toposes, of a number of well-known, classically valid theorems about fields and ordered fields. Classically, these theorems have proofs by contradiction and most involve higher order notions. Here, the theorems are each given a first-order formulation, and this form of the theorem is then deduced using coherent or formally intuitionistic logic. This immediately implies their validity in arbitrary Grothendieck toposes. The main idea throughout is to use coherent theories and, whenever possible, find coherent formulations of formulas which then allow us to call upon the completeness theorem of coherent logic. In one place, the positive model-completeness of the relevant theory is used to find the necessary coherent formulas.The theorems here deal with polynomials or rational functions (in s indeterminates) over fields. A polynomial over a field can, of course, be represented by a finite string of field elements, and a rational function can be represented by a pair of strings of field elements. We chose the approach whereby results on polynomial rings are reduced to results about the base field, because the theory of polynomial rings in s indeterminates over fields, although coherent, is less desirable from a model-theoretic point of view. Ultimately we are interested in the models.This research was originally motivated by the works of Saracino and Weispfenning [SW], van den Dries [Dr], and Bunge [Bu], each of whom generalized some theorems from algebraic geometry or ordered fields to (commutative, von Neumann) regular rings (with unity).


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Cuthbert F. Mhilu

Production of first generation biofuels using food crops is under criticism over sustainability issues on food security. Tanzania is showing active interest in developing second generation biofuels to deal with some of such issues, especially from the feedstock point of view. This paper reports work done to determine energy characteristics of rice and coffee husks. The results show that coffee husks have better energy quality than rice husks, while heating values of coffee are 18.34 MJ/kg and 13.24 MJ/kg for rice husk. Thermogravimetric analysis made for coffee husks blended rice husks at a ratio of 75 : 25% vol. show better material degradation characteristics yielding low residual mass of 23.65%, compared to 26.50% of char and ash remaining in pure rice husks. Derivative thermogravimetric analysis shows comparable hemicellulose degradation peak values of −11.5 and −11.2 and cellulose −3.20 and −2.90 in pure coffee and rice husks, respectively. In coffee and rice husks blends, substantial reductions of hemicellulose and cellulose peaks were observed. Use of coffee and rice husks blends applying high temperature gasification would reduce the latter’s flammability, while increasing its flame retention characteristics, hence offering opportunities for production of clean syngas in a sustainable manner.


2014 ◽  
Vol 26 (6) ◽  
pp. 459-466 ◽  
Author(s):  
Hedvika Kovandová ◽  
Robert Válka

The paper deals with safety of transport from the point of view of an important social problem, which are accidents at railroad (including tramway) and road level crossings, which means compatibility of rail and road vehicles crash. The scale of such accidents can be very wide. Regarding the statistics and frequency of accidents particularly at railway level crossings and tramway level crossings, a collision simulating the collision of a tram and passenger car was experimentally carried out. The experiment took place at the site of testing laboratory of Rail Vehicles Research Institute in Cerhenice. The experiment was conducted with a passenger car Škoda Superb of the first generation that was exposed to two collisions from both sides. Firstly by the impactor for tram headstock tests and secondly by the tram headstock itself. Both the impactor and the headstock were placed on the experimental vehicle for tests of passive safety of rail vehicles. Various speeds were chosen so that the passenger car could be used for two subsequent experiments without the influence on properties of skeleton´s supporting structure.


Organizacija ◽  
2017 ◽  
Vol 50 (2) ◽  
pp. 163-176 ◽  
Author(s):  
Olja Arsenijević ◽  
Dragan Trivan ◽  
Iztok Podbregar ◽  
Polona Šprajc

Abstract Background and Purpose: This paper analyses the strategic aspects of knowledge management in organizations in Serbia, from the theoretical and empirical point of view. In its theoretical part, the paper analyzes the latest literature in the fields of knowledge management, relations between communications strategyes and knowledge management, generations of knowledge management and organizational culture. Design/Methodology/Approach: In its empirical part, the paper deals with determining the level of knowledge management in Serbian organizations through diffrent generations of knowledge management, as well as the problem with explicit and tacit knowledge management. The hypotheses were tested using data colleted from organizatons in Serbia via questionnaire, which consisted of 50 questions to examine five key factors in knowledge management. Results: The results showed that out of 41 indicators, only eight are rated positively. Results of t-test indicate significant distinctions within factors affecting the quality of knowledge management, as well as differences in quality of explicit and tacit knowledge management, therefore they confirmed both hypotheses. Conclusion: The knowledge management projects in organizations in Serbia are initiated, as well as that belonging to the first generation of knowledge management can be defined.


Author(s):  
Maryam Gholami Doborjeh ◽  
Zohreh Gholami Doborjeh ◽  
Akshay Raj Gollahalli ◽  
Kaushalya Kumarasinghe ◽  
Vivienne Breen ◽  
...  

1969 ◽  
Vol 73 (701) ◽  
pp. 449-452
Author(s):  
J. E. Cadoux

The Matra 530 is currently called a second generation air-to-air missile. Indeed the first generation of air-to-air missiles was represented in France by the Nord 5103 which was command-guided, or the Matra 511 which was a semi-active, pure pursuit curve missile. In the second part of the 1950's the requirement was obvious for a sophisticated interception system capable of coping with the high and medium altitude threat represented by heavy and medium bombers. The destruction of this threat required a close link with an interception system composed of ground radars, ground control equipment, sophisticated high performance interceptor aircraft and, as a last link, a very high performance missile. From the French Air Force point of view, the two main characteristics of this missile as the last link of an interceptor system, were first its flexibility in different weather environment and counter measure environment; second, its capability to decrease to the maximum the penetration of the enemy bomber, which meant that the missile should be capable of attacking not only in the rear sector but also in frontal attack and in fact in all sectors around the attacking bomber.


Science ◽  
2011 ◽  
Vol 334 (6052) ◽  
pp. 61-65 ◽  
Author(s):  
M. Mariantoni ◽  
H. Wang ◽  
T. Yamamoto ◽  
M. Neeley ◽  
R. C. Bialczak ◽  
...  

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