Optimization of renewal input (a, c, b) policy working vacation queue with change over time and bernoulli schedule vacation interruption

This paper presents a renewal input single working vacation queue with change over time and Bernoulli schedule vacation interruption under (a, c, b) policy. The service and vacation times are exponentially distributed. The server begins service if there are at least c units in the queue and the service takes place in batches with a minimum of size a and a maximum of size b (a ≤ c ≤ b). The change over period follows if there are (a − 1) customers at service completion instants. The steady state queue length distributions at arbitrary and pre-arrival epochs are obtained. An optimal cost policy is presented along with few numerical experiences. The genetic algorithm and quadratic fit search method are employed to search for optimal values of some important parameters of the system.Publisher's Versio

Models, services and security in modern online social networks

Modern online social networks have revolutionized the world the same way the radio and the plane did, crossing geographical and time boundaries, not without problems, more can be learned, they can still change our world and that their true worth is still a question for the future

Proceedings of the First International Workshop on Sustainable Ultrascale Computing Systems (NESUS 2014): Porto, Portugal

Proceedings of: First International Workshop on Sustainable Ultrascale Computing Systems (NESUS 2014). Porto (Portugal), August 27-28, 2014

Machine Learning

Machine Learning can be defined in various ways related to a scientific domain concerned with the design and development of theoretical and implementation tools that allow building systems with some Human Like intelligent behavior. Machine learning addresses more specifically the ability to improve automatically through experience

Fourth Annual Workshop on Space Operations Applications and Research (SOAR 90)

The proceedings of the SOAR workshop are presented. The technical areas included are as follows: Automation and Robotics; Environmental Interactions; Human Factors; Intelligent Systems; and Life Sciences. NASA and Air Force programmatic overviews and panel sessions were also held in each technical area

LIPIcs, Volume 261, ICALP 2023, Complete Volume

LIPIcs, Volume 261, ICALP 2023, Complete Volum

Irreversible Noise: The Rationalisation of Randomness and the Fetishisation of Indeterminacy

This thesis aims to elaborate the theoretical and practical significance of the concept of noise with regard to current debates concerning realism, materialism, and rationality. The scientific conception of noise follows from the developments of thermodynamics, information theory, cybernetics, and dynamic systems theory; hence its qualification as irreversible. It is argued that this conceptualization of noise is entangled in several polemics that cross the arts and sciences, and that it is crucial to an understanding of their contemporary condition. This thesis draws on contemporary scientific theories to argue that randomness is an intrinsic functional aspect at all levels of complex dynamic systems, including higher cognition and reason. However, taking randomness or noise as given, or failing to distinguish between different descriptive levels, has led to misunderstanding and ideology. After surveying the scientific and philosophical context, the practical understanding of randomness in terms of probability theory is elaborated through a history of its development in the field of economics, where its idealization has had its most pernicious effects. Moving from the suppression of noise in economics to its glorification in aesthetics, the experience of noise in the sonic sense is first given a naturalistic neuro-phenomenological explanation. Finally, the theoretical tools developed over the course of the inquiry are applied to the use of noise in music. The rational explanation of randomness in various specified contexts, and the active manipulation of probability that this enables, is opposed to the political and aesthetic tendencies to fetishize indeterminacy. This multi-level account of constrained randomness contributes to the debate by demystifying noise, showing it to be an intrinsic and functionally necessary condition of reason and consequently of freedom

The corporate renewal dilemma: understanding the influence of the job construct on the resource allocation process in the retail banking industry

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Económicas y Empresariales, Departamento de Organización de Empresas, leída el 07-05-2014Una de las patologías más frecuentes de las empresas modernas es conocida por el término Estancamiento. Más del 90% de las empresas lo sufrirán a lo largo de su ciclo de vida (Olson & Van Bever 2008). Esta patología consiste en una ralentización de la tasa de crecimiento orgánico, que quedará por debajo del umbral de crecimiento sostenible unida a la imposibilidad de retornar a altas tasas de crecimiento. Esta patología sucede en todas las empresas de todos los ámbitos y países. Sin embargo a pesar de haber sido objeto de estudio por parte de la comunidad científica aún nos encontramos lejos de la solución. Las investigaciones previas muestran que este es un problema complejo y cuyas implicaciones exceden el ámbito de un único campo de investigación. Por ejemplo, en la literatura de diseño organizacional existe evidencia de que mecanismos como la Inercia o las Rigideces Organizativas juegan un papel relevante en la generación del Estancamiento. En la literatura de cambio tecnológico se muestran evidencias similares con las Discontinuidades o el fenómeno de exceder las expectativas de los clientes. La literatura de marketing estratégico también muestra evidencias que la unen con este problema. Sin embargo, a pesar de la extensa literatura, cada una con sus propias conclusiones, no hay evidencias de estudios que muestren una solución clara al problema del Estancamiento. Esta tesis analiza este problema usando una metodología estructurada en dos partes. En la primera parte se utiliza una metodología que controla específicamente las variables causales y cuya unidad de análisis es el constructo “Job”, que ha sido identificado previamente en la literatura a nivel inductivo. El constructo “Job” incluye información relacionada con la industria, el diseño organizacional, el cliente y el producto. En la segunda parte se testea la influencia de la Hipótesis Espejo en la generación de Estancamiento. Posteriormente se procede a introducir el constructo “Job” y se observa si su efecto anula la influencia de la Hipótesis Espejo devolviendo a la empresa a tasas de crecimiento superiores a su crecimiento sostenible. La primera parte del estudio se elaboró con una metodología llamada Multi Método que combina datos cualitativos y cuantitativos (Tashakkori and Teddlie, 2003). Este método además controla específicamente la tipología de las variables, poniendo especial atención las que son exógenas y endógenas, inductivas y deductivas y particularmente las que son causales en relación a las que son descriptivas. En total se obtuvieron 62 variables deductivas (provenientes del cuerpo teórico) y 34 variables inductivas (que emergen a lo largo de la investigación). El estudio de campo se realizó en la industria de la banca minorista en España. La base de datos final recogió 106.452 registros. Esta riqueza de los datos permitió obtener varios constructos “Job” y compararlos en un estudio clínico. Los resultados de dicho estudio muestran que la estructura primaria descrita en la literatura se confirma y se amplía con nuevas estructuras que son completamente nuevas e inéditas en la literatura. La segunda parte del estudio se elaboró con una metodología llamada Método Mixto (Dillman, 2006; Edmondson and McManus, 2007) y sus datos provinieron de una encuesta también realizada en la industria de la banca. La encuesta obtuvo 306 registros, lo cual indica una tasa de respuesta excepcionalmente alta en esta industria. La encuesta sirvió para: 1) Triangular los resultados de la primera parte del estudio y de esta forma replicar los resultados del Multi Método; 2) Aislar la influencia de la Hipótesis Espejo en el proceso de Estagnación y; 3) Aislar la influencia del constructo “Job” en la teoría de asignación de recursos y cuál es el mecanismo por el que es capaz de generar nuevas iniciativas de alto crecimiento. En las conclusiones de esta tesis se explican las razones que causan que la Hipótesis Espejo actúe como inhibidor de las nuevas iniciativas de alto margen (actúa eliminando el Impetus). Además se concluye que mecanismos como la Inercia o las Rigideces Organizativas no son causas sino síntomas generados por la Hipótesis Espejo. Una conclusión adicional es que el constructo “Necesidad”, actualmente predominante en marketing estratégico, no contiene la información necesaria para anular el efecto de la Hipótesis Espejo ya que ésta además actúa con diferente intensidad en cada área funcional de la empresa. La tesis concluye con un experimento clínico en el que se reemplaza el constructo “Necesidad” por el constructo “Job”. Los resultados evidencian cómo la información contenida en el constructo “Job” es capaz de neutralizar la Hipótesis Espejo a través de la reasignación de recursos a las nuevas iniciativas de alto margen (actúa devolviendo el Impetus a las nuevas iniciativas del alto margen). Estas evidencias permiten concluir que el constructo “Job” es capaz de recuperar una empresa que se encuentra con un problema de Estancamiento devolviéndola a tasas de crecimiento sosteniblesOver their lifetime, more than 90% of the firms in the world will inevitably suffer from a process called Stagnation, where they will experience a substantial and abrupt growth slowdown from which they will never recover, hence never experiencing sustainable growth again (Olson & Van Bever 2008). This happens irrespective of how effective their management is, in which country they are located or the industry where they operate. Management scholars have been researching this problem for a long time, but the formula to prevent this from happening or to regain new net growth remains elusive. Previous research suggests that this challenge is very complex and that its implications remain outside of the scope of a single field of study. For instance, at the organizational level mechanisms such as Inertia, Competency Traps or Corporate Rigidities have been identified. At the technological level the role of Discontinuities, Technological Change and Overshooting have also been clearly delineated. At the Marketing level the limitations of consumer information and the foundational blocks of consumer research have also been identified. Despite this extensive literature results are not improving, it appears that even combining all these factors it’s still not enough to prevent Stagnation. This thesis tackles this challenge in a different way and using a two‐step methodology. First it uses a new methodology that specifically controls for causality while it isolates and understands the anatomy of a new corporate “cell” that has been defined previously at the inductive level in the literature and that predicts consumer behavior with a substantially higher level of accuracy. This “cell”, named the Job Construct contains multilevel information that affects the industry, the firm’s Organizational Design, the Consumer and the Product. Second we test the influence of the Mirroring Hypothesis as the causal variable that generates Competency Traps, Inertia and Corporate Rigidities. We then subsequently introduce the Job Construct in the research to clinically control for its influence and in particular for knowing if this new “cell” is capable of overcoming the influence on the Mirroring Hypothesis resulting in the re‐engagement of the firm in new net growth. Two research methodologies were used. First a Qualitative – Quantitative Sequential Multi‐Method Model (Tashakkori and Teddlie, 2003) was used to isolate and understand the anatomy of the Job Construct. This model was designed emphasizing the control of exogenous and endogenous variables, inductive and deductive variables and causal and attribute‐based variables. This model is based on Qualitizing data and replacing most of the qualitative steps performed in any given ethnographic study with quantitative methods. A total of 62 Deductive codes were obtained from four literature reviews and were consistently tested in the research. In addition 34 Inductive codes emerged from the research being most of them completely new to the extant literatures examined. Twelve datasets collected from the Spanish Retail Banking industry were used to first confirm the existence and then isolate and examine in detail the anatomy of the Job Construct in three Circumstances. The richness of the study (in total 106,452 codes were elicited) allowed to clinically compare the different Job Constructs that were obtained and comprehend in details their inner workings. Three of their branches – that had been Inductively described in the extant literature – were confirmed but also two more branches were also identified. An additional two were observed but not subsequently tested because of the limitations of the Unit of Analysis. The second research methodology used in this research was a Mixed Method (Dillman, 2006; Edmondson and McManus, 2007). The total survey response was 306 registers, this large sample survey analysis was used to: 1) Understand the influence of the Mirroring Hypothesis in the process of Stagnation of firms; 2) Capture the influence of the Job Construct on the Resource Allocation Process and how it reignites new net growth and 3) Triangulate the findings on the Job Construct that had been obtained using the Multi‐Method Model. This study shows that the Mirroring Hypothesis is what’s causing that new High‐Margin initiatives fail to gain Impetus. It shows that Inertia, Competency Traps and Organizational Rigidities are lagging effects of the Mirroring Hypothesis. Another finding is that the Needs Construct doesn’t contain the information necessary to overcome the Mirroring Hypothesis and that the Mirroring Hypothesis doesn’t block uniformly the firm but that its influence is different in each Functional Unit. The study concludes that the Job Construct contains the information necessary to overcome the Mirroring Hypothesis’ rigidities and provide again Impetus to new High‐Margin initiatives. Lastly this study shows that the Job Construct strength can recover a firm that’s suffering from Stagnation, re‐engaging it in new net‐growthDepto. de Organización de EmpresasFac. de Ciencias Económicas y EmpresarialesTRUEunpu