343 research outputs found
Can PPAD hardness be based on standard cryptographic assumptions?
No full textWe consider the question of whether PPAD hardness can be based on standard cryptographic assumptions, such as the existence of one-way functions or public-key encryption. This question is particularly well-motivated in light of new devastating attacks on obfuscation candidates and their underlying building blocks, which are currently the only known source for PPAD hardness. Central in the study of obfuscation-based PPAD hardness is the sink-of-verifiable-line (SVL) problem, an intermediate step in constructing instances of the PPAD-complete problem source-or-sink. Within the framework of black-box reductions, we prove the following results: (i) average-case PPAD hardness (and even SVL hardness) does not imply any form of cryptographic hardness (not even one-way functions). Moreover, even when assuming the existence of one-way functions, average-case PPAD hardness (and, again, even SVL hardness) does not imply any public-key primitive. Thus, strong cryptographic assumptions (such as obfuscation-related ones) are not essential for average-case PPAD hardness. (ii) Average-case SVL hardness cannot be based either on standard cryptographic assumptions or on average-case PPAD hardness. In particular, average-case SVL hardness is not essential for average-case PPAD hardness. (iii) Any attempt for basing the average-case hardness of the PPAD-complete problem source-or-sink on standard cryptographic assumptions must result in instances with a nearly exponential number of solutions. This stands in striking contrast to the obfuscation-based approach, which results in instances having a unique solution. Taken together, our results imply that it may still be possible to base PPAD hardness on standard cryptographic assumptions, but any such black-box attempt must significantly deviate from the obfuscation-based approach: It cannot go through the SVL problem, and it must result in source-or-sink instances with a nearly exponential number of solutions
A high performance transparent resistive switching memory made from ZrO2/AlON bilayer structure
No full textIn this study, the switching properties of an indium tin oxide (ITO)/zirconium oxide (ZrO2)/ITO single layer device and those of a device with an aluminum oxynitride (AlON) layer were investigated. The devices with highly transparent characteristics were fabricated. Compared with the ITO/ZrO2/ITO single layer device, the ITO/ZrO2/AlON/ITO bilayer device exhibited a larger ON/OFF ratio, higher endurance performance, and superior retention properties by using a simple two-step forming process. These substantial improvements in the resistive switching properties were attributed to the minimized influence of oxygen migration through the ITO top electrode (TE), which can be realized by forming an asymmetrical conductive filament with the weakest part at the ZrO2/AlON interface. Therefore, in the ITO/ZrO2/AlON/ITO bilayer device, the regions where conductive filament formation and rupture occur can be effectively moved from the TE interface to the interior of the device. Published by AIP Publishing.Ministry of Science and Technology, Taiwan [NSC 102-2221-E009-134-MY3]SCI(E)[email protected]
Entrepreneurship in Northeast Brazil : an evaluation of business incubators in the region
No full textMestrado em Economia e Gestão de Ciência, Tecnologia e InovaçãoThis research has been conducted in the Brazil’s Northeast region, economically the weakest region in the country. A total of 35 business incubators (97%) and 93 firms (29%) were surveyed by questionnaire and interviews were conducted in 14 incubators in order to map the region’s incubators and to evaluate the practice and the possible impact of this economic development tool.
In our analysis we found evidence of structural and administrative failures, absence of adequate business development and financial instability due to a low level of public investment. Since there is no clear policy, each incubator is an independent initiative of either a public or private university, a technology park, a science department of local government or a non-profit organization.
The lack of adequate finance has as a consequence the prevalence of software firms on the expense of other innovative sectors and the abundance of part-time incubator and firm personnel and, more importantly, it also brings about part-time entrepreneurs.
Apart of a relatively small fraction of strong and effective incubators, the majority of the surveyed incubators performs an incorrect firm selection process, does not define a fixed period for firms graduating from the incubator and in general provides the firm with facilities but not with consistent consulting on most of the relevant areas of business development.
The dissertation concludes that this economic development tool can be put to greater advantage of the region, if given policy and managerial changes are introduced in the near future.Esta pesquisa foi realizada no Nordeste do Brasil, a região mais pobre do país. 35 incubadoras de empresas (97%) e 93 empresas incubadas (29%) responderam questionários e foram realizadas entrevistas em 14 incubadoras, a fim de mapear as incubadoras da região e avaliar a prática e o possível impacto desse instrumento de desenvolvimento económico.
O nosso estudo é inspirado na política de incubadora tecnológica pública israelita. Um programa do governo com 22 anos de operação, que utiliza um modelo de incubadoras privadas com amplo investimento público. O caso de Israel fornece um ponto de referência que pode ajudar a comparar e compreender melhor o potencial da incubadora no nordeste do Brasil na sua forma actual.
Na nossa análise encontramos evidências de falhas estruturais e administrativos, ausência de comportamento empresarial e instabilidade financeira devido a um baixo nível de investimento público. Como não existe uma política clara na região, cada incubadora é uma iniciativa independente de um instituto de ensino público ou privado, um parque tecnológico, departamento de ciência do governo local ou outra organização sem fins lucrativos.
A falta de recursos financeiros traz a prevalência de empresas do sector informático em detrimento de outros sectores inovadores e a abundância de funcionários em tempo parcial nas incubadoras e nas firmas e o mais importante, o empreendedorismo a tempo parcial.
Além de uma parte relativamente pequena de incubadoras fortes e eficazes, a maioria realiza um processo incorrecto de selecção de empresa, não define período fixo para a incubação e em geral, fornece as empresas com instalações, mas falta uma consultoria consistente e intervenção pró-activa
Entrepreneurship in Northeast Brazil : an evaluation of business incubators in the region
No full textMestrado em Economia e Gestão de Ciência, Tecnologia e InovaçãoThis research has been conducted in the Brazil’s Northeast region, economically the weakest region in the country. A total of 35 business incubators (97%) and 93 firms (29%) were surveyed by questionnaire and interviews were conducted in 14 incubators in order to map the region’s incubators and to evaluate the practice and the possible impact of this economic development tool.
In our analysis we found evidence of structural and administrative failures, absence of adequate business development and financial instability due to a low level of public investment. Since there is no clear policy, each incubator is an independent initiative of either a public or private university, a technology park, a science department of local government or a non-profit organization.
The lack of adequate finance has as a consequence the prevalence of software firms on the expense of other innovative sectors and the abundance of part-time incubator and firm personnel and, more importantly, it also brings about part-time entrepreneurs.
Apart of a relatively small fraction of strong and effective incubators, the majority of the surveyed incubators performs an incorrect firm selection process, does not define a fixed period for firms graduating from the incubator and in general provides the firm with facilities but not with consistent consulting on most of the relevant areas of business development.
The dissertation concludes that this economic development tool can be put to greater advantage of the region, if given policy and managerial changes are introduced in the near future.Esta pesquisa foi realizada no Nordeste do Brasil, a região mais pobre do país. 35 incubadoras de empresas (97%) e 93 empresas incubadas (29%) responderam questionários e foram realizadas entrevistas em 14 incubadoras, a fim de mapear as incubadoras da região e avaliar a prática e o possível impacto desse instrumento de desenvolvimento económico.
O nosso estudo é inspirado na política de incubadora tecnológica pública israelita. Um programa do governo com 22 anos de operação, que utiliza um modelo de incubadoras privadas com amplo investimento público. O caso de Israel fornece um ponto de referência que pode ajudar a comparar e compreender melhor o potencial da incubadora no nordeste do Brasil na sua forma actual.
Na nossa análise encontramos evidências de falhas estruturais e administrativos, ausência de comportamento empresarial e instabilidade financeira devido a um baixo nível de investimento público. Como não existe uma política clara na região, cada incubadora é uma iniciativa independente de um instituto de ensino público ou privado, um parque tecnológico, departamento de ciência do governo local ou outra organização sem fins lucrativos.
A falta de recursos financeiros traz a prevalência de empresas do sector informático em detrimento de outros sectores inovadores e a abundância de funcionários em tempo parcial nas incubadoras e nas firmas e o mais importante, o empreendedorismo a tempo parcial.
Além de uma parte relativamente pequena de incubadoras fortes e eficazes, a maioria realiza um processo incorrecto de selecção de empresa, não define período fixo para a incubação e em geral, fornece as empresas com instalações, mas falta uma consultoria consistente e intervenção pró-activa
Entrepreneurship in Northeast Brazil : an evaluation of business incubators in the region
No full textMestrado em Economia e Gestão de Ciência, Tecnologia e InovaçãoThis research has been conducted in the Brazil’s Northeast region, economically the weakest region in the country. A total of 35 business incubators (97%) and 93 firms (29%) were surveyed by questionnaire and interviews were conducted in 14 incubators in order to map the region’s incubators and to evaluate the practice and the possible impact of this economic development tool.
In our analysis we found evidence of structural and administrative failures, absence of adequate business development and financial instability due to a low level of public investment. Since there is no clear policy, each incubator is an independent initiative of either a public or private university, a technology park, a science department of local government or a non-profit organization.
The lack of adequate finance has as a consequence the prevalence of software firms on the expense of other innovative sectors and the abundance of part-time incubator and firm personnel and, more importantly, it also brings about part-time entrepreneurs.
Apart of a relatively small fraction of strong and effective incubators, the majority of the surveyed incubators performs an incorrect firm selection process, does not define a fixed period for firms graduating from the incubator and in general provides the firm with facilities but not with consistent consulting on most of the relevant areas of business development.
The dissertation concludes that this economic development tool can be put to greater advantage of the region, if given policy and managerial changes are introduced in the near future.Esta pesquisa foi realizada no Nordeste do Brasil, a região mais pobre do país. 35 incubadoras de empresas (97%) e 93 empresas incubadas (29%) responderam questionários e foram realizadas entrevistas em 14 incubadoras, a fim de mapear as incubadoras da região e avaliar a prática e o possível impacto desse instrumento de desenvolvimento económico.
O nosso estudo é inspirado na política de incubadora tecnológica pública israelita. Um programa do governo com 22 anos de operação, que utiliza um modelo de incubadoras privadas com amplo investimento público. O caso de Israel fornece um ponto de referência que pode ajudar a comparar e compreender melhor o potencial da incubadora no nordeste do Brasil na sua forma actual.
Na nossa análise encontramos evidências de falhas estruturais e administrativos, ausência de comportamento empresarial e instabilidade financeira devido a um baixo nível de investimento público. Como não existe uma política clara na região, cada incubadora é uma iniciativa independente de um instituto de ensino público ou privado, um parque tecnológico, departamento de ciência do governo local ou outra organização sem fins lucrativos.
A falta de recursos financeiros traz a prevalência de empresas do sector informático em detrimento de outros sectores inovadores e a abundância de funcionários em tempo parcial nas incubadoras e nas firmas e o mais importante, o empreendedorismo a tempo parcial.
Além de uma parte relativamente pequena de incubadoras fortes e eficazes, a maioria realiza um processo incorrecto de selecção de empresa, não define período fixo para a incubação e em geral, fornece as empresas com instalações, mas falta uma consultoria consistente e intervenção pró-activa
Technological forecasting and regulatory assessment: an application to assisted reproductive technologies
No full textTésis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias Económicas y Empresariales, Departamento de Estructura Económica y Economía del Desarrollo, Fecha de lectura: 08-11-2019The aim of this thesis is to assess the trajectories of artificial reproductive technology (ART) and its pace of diffusion by identifying the factors that influence this process. This general objective can be split into the following specific objectives. First, to conduct a technology forecasting exercise in order to better understand the potential developments in IVF, PGD, and genetic engineering. Second, to identify the factors affecting regulation and priority setting regarding ART and to review the responses to technological and market developments in the field, through a regulatory assessment and a comparative analysis between Israel and Spain. Third, to assess the regulatory trends that may (or not) lead to the “geneticization” of reproduction (i.e. the shift of reproduction into the lab due to the ability to select or design genetic traits of embryos). These three sub-objectives define the structure of this thesis around three chapters, which have been drafted as independent papers to be published in scientific journal
Regulating reproductive genetic services: dealing with spiral-shaped processes and techno-scientific imaginaries
No full textPurpose: We have been inquiring into the diffusion process of reproductive genetic services (RGS) and the viability of geneticization in human reproduction.
Method: A 2-round modified-Delphi survey was applied amongst Israeli and Spanish experts to analyze regulatory attitudes and expectations about the future applications of RGS. We argue that an explanation of RGS diffusion based on a ‘technology-push’ impulse should be complemented by a ‘demandpull’ approach, which underscores the importance of regulatory frameworks and demand-inducing policies. The diffusion of RGS is advancing in a ‘spiralshaped’ process where technology acts as a cause and effect simultaneously, modulating social acceptance and redefining the notions of health and responsibility along the way.
Results: We suggest that there is a ‘grey-zone’ of RGS regulations regarding four procedures: the use of germline genome modification (GGM) for severe monogenic disorders, preimplantation genetic testing (PGT) for detection of chromosomal abnormalities, PGT for multifactorial diseases, and PGT with whole-exome screening.
Conclusions: Although far from the geneticization of human reproduction, our findings suggest that, since techno-scientific imaginaries tend to shape regulations and thus favor the diffusion of RGS, policymakers should pay attention to those procedures by focusing on good practices and equity while providing sound information on potential risks and expected success rates. A broad and inclusive societal debate is critical for overcoming the difficulty of drawing a clear line between medical and nonmedical uses of genetic selection and engineering while searching for the right balance between allowing reproductive autonomy and protecting the public interest.Depto. de Economía Aplicada, Pública y PolíticaFac. de Ciencias Económicas y EmpresarialesTRUEpu
Product structure extension of the Alon--Seymour--Thomas theorem
No full textAlon, Seymour and Thomas [1990] proved that every -vertex graph excluding as a minor has treewidth less than . Illingworth, Scott and Wood [2022] recently refined this result by showing that every such graph is a subgraph of some graph with treewidth , where each vertex is blown up by a complete graph of order . Solving an open problem of Illingworth, Scott and Wood [2022], we prove that the treewidth bound can be reduced to while keeping blowups of order . As an extension of the Lipton--Tarjan theorem, in the case of planar graphs, we show that the treewidth can be further reduced to , which is best possible. We generalise this result for -minor-free graphs, with blowups of order . This setting includes graphs embeddable on any fixed surface.Title changed, author added, and results for -minor-free graphs added in v2. Referee comments incorporated into v
Assisted reproduction in Spain, outcome and socioeconomic determinants of access
No full textAbstract Research question We analyzed two questions. First, the effectiveness of public Assisted Reproductive Technologies (ART) in Spain compared with private ones, measured by the time since initiating ART treatment until achieving pregnancy, accounting for age and socioeconomic factors. Second, socioeconomic determinants of access to ART, referring primarily to financial means derived by employment, income, and wealth. Design We applied statistical models on data extracted from the national Spanish Fertility Survey from 2018. The first topic was analyzed by competing risk survival analysis conducted on a sample of 667 women who initiate ART treatment since 2000. The second, by a Bivariate Probit model conducted on a sample of 672 women older than 41 years who required ART services. Results The first analysis raised that throughout the treatment, patients treated exclusively in private clinics had on average a higher cumulative incidence of becoming pregnant compared with patients who approached public clinics. The second analysis raised that both higher household equivalent income and higher education increase the likelihood of accessing ART in a private clinic and decrease the tendency of accessing public clinics or failing to access any service. Moreover, being single decreases the likelihood of accessing public clinics or ART services in general. Conclusions Long waiting periods could be the main reason for the lower incidence of getting pregnant in public healthcare, explaining why patients choose private over public care. We develop a broader discussion over the extent of Spanish public funding of ART, the unequal medical outcome, and potential options for optimization
UCC Actors Hit the Beach in "Never Swim Alone"
No full textPress ReleaseDaniel MacIvorNever Swim Alon
- …
