Theory Of Conversion Research Articles

Simultaneous parametric generation and up-conversion of entangled optical images

A quantum theory of parametric amplification and frequency conversion of an optical image in coupled nonlinear optical processes that include one parametric amplification process at high-frequency pumping and two up-conversion processes in the same pump field is developed. The field momentum operator that takes into account the diffraction and group velocities of the waves is used to derive the quantum equations related to the spatial dynamics of the images during the interaction. An optical scheme for the amplification and conversion of a close image is considered. The mean photon number density and signal-to-noise ratio are calculated in the fixed-pump-field approximation for images at various frequencies. It has been established that the signal-to-noise ratio decreases with increasing interaction length in the amplified image and increases in the images at the generated frequencies, tending to asymptotic values for all interacting waves. The variance of the difference of the numbers of photons is calculated for various pairs of frequencies. The quantum entanglement of the optical images formed in a high-frequency pump field is shown to be converted to higher frequencies during the generation of sum frequencies. Thus, two pairs of entangled optical images are produced in the process considered.

Fractional bit encoded spatial modulation (FBE-SM)

In this Letter, we introduce fractional bit encoded (FBE)-spatial modulation (SM), which is a novel and more versatile SM scheme that allows the transmitter to be equipped with an arbitrary number of antennas. The solution is based on the theory of modulus conversion, and is especially useful for compact mobile devices where cost and space constraints pose fundamental limits on the achievable bit rate. Numerical results will show that FBE-SM can offer design flexibility and the desired trade-off in terms of attainable performance and capacity.

Relativistic theory of mode conversion at plasma frequency

The equations governing the mode conversion between an electromagnetic wave and the plasma wave are derived from the relativistic Vlasov equation. They are further reduced to a two dimensional matrix equation involving only two electric field components. It is shown that the mode conversion efficiency diminishes to zero at both 0° and 90° of incidence angles, becomes insignificant beyond 45° and tends to improve with higher plasma temperature.

Disability Nationalism in Crip Times

The article puts queer postcolonial and transnational theory in conversation with studies in order to reflect on what might be called, adapting Jasbir K. Puar, disability nationalism in crip times. Surveying the ways that queer theory has analyzed gay identity and the heterosexual–homosexual binary in postcolonial and transnational contexts, the article considers some of the reasons why studies has not followed the same trajectory in relation to analyses of identity and the able-bodied–disabled binary. Through a reading of Victoria Brittain and Gillian Slovo's play Guantanamo: Honor Bound to Defend Freedom, the article contends that the geopolitics of in the current world order require analyses of bodies beyond borders—specifically, of impairments that are not immediately legible within the identity-based or nationalist terms that generally characterize the field and movement.

A Novel Approach for Collaborative Pair Programming

Introduction Engineering education accreditation agencies of US, UK, Australia, Japan, and Singapore have transformed their accreditation process from the traditional resource-based approach to outcome-based approach. Competencies such as ability to apply knowledge, design skills, problem solving skills, technical competence, ability to work in multidisciplinary teams, communication skills, sensitivity towards global, societal, and environmental issues, sensitivity towards ethical and professional issues, and readiness for lifelong learning have been identified as necessary (Goel 2006a). Goel (2006b) has classified core engineering and general professional competencies with reference to the requirements of Indian IT industry. Problem solving ability has been rated as the pivotal skill. Nine critical competencies include a mix of engineering and general professional skills. These are analysis/methodological skills, basic engineering proficiency, development know-how, teamwork skills, English language skills, presentation skills, practical engineering experience, leadership skills, and communication skills. Consequently, it is mandatory that all courses in engineering curricula should consciously and directly contribute towards the development of these competencies. Today, organizations have offices in multiple locations with teams interacting across various geographical sites, sometimes even in different time zones. Big software projects are divided across locations, and people across different sites are expected to combine their individual works to complete the project work. Further, programmers need to develop the ability to comprehend the programs developed by others and also to write programs that can be easily comprehended by other programmers. Increasing dependence on large amounts of Free and Open Source Software (FOSS) makes it even more crucial. However, a serious shortcoming of the typical undergraduate engineering education process is neglecting to train students to work with other programmers. Usually in a four-year engineering course, collaborative effort and teamwork is done only in the later years, i.e., in the third and fourth year. Even then the collaboration is driven more by division of labor due to size rather than complexity. Many a times, the assignment or project is designed after forming the groups in the classroom, when the teacher knows the strength of a particular group. Such approaches do not necessarily develop teamwork skills. Researchers have felt the need for a way to facilitate students to work together with clearly defined boundaries (Cliburn, 2003). Collaborative learning focuses on the role of peer work for educational success. Vygotsky in his seminal social development theory proposed that social interaction plays a fundamental role in the process of cognitive development (Goldfarb, 2001). One of key assumptions of Brunner's model of constructivist learning is a social enterprise (Driscoll, 2004). Pask's Conversation theory is founded on the idea that learning occurs through conversations with instructors or peers (Kutay, 2005). As per the social learning theory of Bandura, gaining insights into others' practices can be a valuable experience (Ladyshewsky & Ryan, 2002). Incorporating social learning theory into their experiment, these authors report that peer coaching provided the learners the benefits of enhanced knowledge, cognition, and metacognition. Lave and Wenger (1991) proposed situated learning theory on the central idea that learning involves a process of engagement in a 'community of practice.' From the perspective of this theory, learning is not seen as the acquisition of knowledge by individuals, but as a process of social participation (Smith, 2007). Dillenbourg (1999) elaborated on collaborative learning as follows: ... a situation in which particular forms of interaction among people are expected to occur, which would trigger learning mechanisms, but there is no guarantee that the expected interactions will actually occur. …

ON MODELINGThe language/action model of conversation

Editor's Note: In last year's January + February issue Usman Haque, Paul Pangaro, and I described several types of interaction---reacting, regulating, learning, balancing, managing, and conversing. In the July + August 2009 issue, Paul Pangaro and I described several types of conversing---agreeing, learning, coordinating, and collaborating---and we proposed using models based on Gordon Pask's Conversation Theory as a guide for improving human-computer interaction. Peter Jones responded, noting that there are other models of conversation and prior work in bringing conversation to human-computer interaction in particular Winograd and Flores 1986 work with The Coordinator. We agree on the importance of The Coordinator and invited Peter to outline the history of models of conversation and their relationship to HCI. His response follows.---Hugh Dubberly

Applications de la théorie des négociations conversationnelles de Kerbrat-Orecchioni et de la notion de stratégie à l’analyse des messages asynchrones de l’interaction virttuelle

The written interactive register of internet discourse became the generous source for contemporary linguistic studies. This article tries to explain how to fit a modern conversational theory of C. Kerbrat- Orecchioni to the analysis of interaction between humans in the computer asynchronous communication. The conclusions reached at intend to update notions like conversational strategy, conversational negotiation so as to apply them to the new communication means.

Is there a need for a maxim of politeness?

In this article two arguments are given in support of a maxim of politeness. The first argument is that assuming a maxim is part of the best explanation of polite behaviour, considering the problems, which Brown and Levinson's theory and Fraser and Nolen's conversational contract theory have, and which a maxim-based theory does not have. The second argument is that the maxim of politeness is part of rational conversation among potentially aggressive parties. This leads to a new Gricean theory of politeness: the maxim of politeness is seen as an additional conversational maxim under the Cooperative Principle in rational conversations among potentially aggressive parties. The content of the maxim is then determined face-theoretically, incorporating some of Brown and Levinson's ideas into the Gricean theory.

“Natural” conversation: A treatment for severe aphasia

Background: Many treatment approaches based on different concepts of aphasia have been proposed. Nowadays two main approaches face each other: the impairment- and the consequences-based approaches. The impairment-based approach draws directly from cognitive neuropsychology and is aimed at improving the linguistic deficit. The consequences-based approach (or functional or psychosocial approach) has its roots in the pragmatic approach and endeavours to reduce the consequences of aphasia in daily living. Aims: The aim of this study is to present a treatment for severe aphasia that partially reconciles the two approaches. It incorporates some principles of the impairment-based approach and utilises them in a “natural” situation that has a direct impact on the daily life of patients with aphasia. Methods & Procedures: The description of the characteristic of a conversation between two normal interlocutors serves to illustrate how a theory of conversation can help guide the clinician's behaviour during “natural” conversation/rehabilitation with a severely aphasic patient. Application of the conversation/rehabilitation treatment is illustrated by the case of Mr I, a global aphasic patient 18 months post-onset who underwent 9 months of treatment. Outcomes & Results: Positive outcome was obtained. Mr I was initially unable to keep in contact with anybody or even understand that others were trying to interact with him. After treatment, his approach to others had substantially changed. He showed interest in what happened around him and was capable of sustaining a conversation if his interlocutors took some simple measures to facilitate his comprehension. Conclusions: The conversation/rehabilitation treatment partly reconciles the impairment- and consequences-based approaches and this study demonstrates that at least for one man with aphasia, Mr I, the treatment was successful.

Recent advances in direct solar thermal power generation

The recent energy crisis and environmental burden are becoming increasingly urgent and drawing enormous attention to solar-energy utilization. Direct solar thermal power generation technologies, such as thermoelectric, thermionic, magnetohydrodynamic, and alkali-metal thermoelectric methods, are among the most attractive ways to provide electric energy from solar heat. On the one hand, these methods have the potential to be more efficient than traditional ways since they can convert heat to electricity directly without experiencing the conventional intermediate mechanical energy conversion process; on the other hand, these electricity generators are generally silent, reliable, and scalable, making them very suitable to serve as a distributed power generation system for certain specialized fields, such as military and space applications. A lot of effort has been devoted to investigate the energy conversion theory and practical applications thus far. This paper is intended to present a thorough review on recent advances in developing the thermoelectric, thermionic, magnetohydrodynamic, and alkali-metal thermoelectric technologies for direct solar thermal power generation. Both the fundamental issues and latest application research are illustrated and critical issues are discussed. The paper concludes with a description of future developments expected in the subjects covered.

STEP (Solar Thermal Electrochemical Photo) Generation of Energetic Molecules: A Solar Chemical Process to End Anthropogenic Global Warming

In this study, a solar hybrid theory is derived for the electrosynthesis of energetic molecules at efficiency greater than that for the solar energy conversion efficiency of photovoltaics. The theory distinguishes radiation that drives photovoltaic charge transfer and applies all excess energy to heat and decrease the energy of endothermic electrolysis reactions. The theory for this original process is derived for the solar generation of energetically rich chemicals, including chlorine, iron, aluminum, magnesium, lithium, and sodium, and to proactively convert anthropogenic CO2 generated in burning fossil fuels. The process directs energy sufficient (super-bandgap) sunlight to drive photovoltaic charge transfer, and all remaining (sub-bandgap and excess super-bandgap energy) sunlight to heat and decrease the energy of an electrolysis reaction. In a 650 °C molten carbonate electrolysis configuration, from the STEP (solar thermal electrochemical photo) conversion theory, sunlight will recycle and remove CO2...

Gordon Pask: exchanges between cybernetics and architecture and the envisioning of the IE

PurposeThe purpose of this paper is to study a series of exchanges between cybernetics and the arts, focusing on Pask's lifelong envisioning of the so‐called information environment (I.E). It follows the author's previous PhD dissertation which was concerned with the exchanges between systems research and architecture; Gordon Pask et al.; and a couple of outstanding architectural projects related to systems and computation.Design/methodology/approachThis paper was mainly supported by archival research of Gordon Pask's Archive (held at the time by his daughter) and Cedric Price's Archive (held at the Canadian Centre for Architecture); supplemented with interviews and bibliographical research (research was made possible by a FCT grant – POCI 2010).FindingsThe paper details and discusses exchanges between the fields of cybernetics and the arts; and it focuses on Pask's lifelong exchange with architecture and the manifestation of his ideas in this field. One highlights, among others, Pask's exchanges within the British milieu and the AMG during the 1960s and 1970s; the seminal manifestations of his main C2 achievement – the Conversation Theory – in the field of architecture; and his later architectural performance.Research limitations/implicationsThe previous primary archival research conducted at Pask's daughter house, is being expanded by the author through use of new material.Originality/valueThis paper is intended for historians of sciences and the arts. It briefly overviews Pask's well‐known main works and, in addition, it includes reference to some rare little‐known materials.

Value generation in e‐government from service‐based IT integration

PurposeUnderstanding how value is actually generated in e‐government projects is one of the most challenging, and relevant, issues in e‐government research. This paper aims to investigate the contribution of service‐based information technology (IT) integration for generating value in the public sector, proposing a theoretical framework based on the theory of IT conversion effectiveness.Design/methodology/approachThe paper illustrates this novel approach to electronic government evaluation with an exploratory case study of a service‐based IT integration project developed by the City of Genoa, showing how and why IT integration can substantially contribute to value generation in the public sector.FindingsContrarily to what one would expect according to the original theory of IT conversion effectiveness, value generation may happen even with no substantial growth in the pre‐existing IT asset portfolio. In fact, what is truly important is not only the availability of IT assets (policy output), but also their proper use (policy outcome) and their final effects on policy takers (policy impact). The case study shows how a low‐cost and small IT integration project based on agile information system development practices can significantly leverage the legacy systems, enhancing the overall degree of IT conversion effectiveness (first stage), with expected positive effects on policy outcomes (second stage) and policy impacts (third stage). The enabling effect of the web services technology has a central role in the overall value generation process.Originality/valueWhile addressing a literature void in the context of public sector, this theoretical approach is substantial as it can be used to evaluate and maximize the value generated by e‐government projects, with a special focus on service‐based IT integration projects.

Prognosis time: Towards a geopolitics of affect, debility and capacity

This article brings into conversation theories of affect, particularly those emerging from technoscience criticism that foreground bodily capacities for affecting or being affected, for change, evolution, transformation, and movement, and studies of disability and debility which complicate these notions of capacity, even while privileging identity-based rights and representational politics that might reinscribe other forms of normativity. I argue for a deconstruction of what ability and capacity mean, affective and otherwise, and to push for a broader politics of debility that puts duress on the seamless production of abled-bodies in relation to disability. Central to my discussion will be formulations of risk, calculation, prognosis, statistical probability, and population construction, whereby identity is understood not as essence, but as risk coding. Affect is therefore a site of bodily creative discombobulation and resistance but one that is also offered up for increasing monitoring and modulation.

Source locations of narrowband radio emissions detected at Saturn

Since Cassini's arrival at Saturn in 2004, the Radio and Plasma Wave Science instrument has detected numerous narrowband (NB) radio emission events. These emissions, mostly detected around 5 and 20 kHz, usually occur periodically for several days after intensifications of Saturn kilometric radiation. We present calculations based on an electron density profile of Saturn's plasma torus and a dipole magnetic field model showing that the NB emissions originate from the northern and southern edges of Saturn's plasma torus at L shells ∼ 8 to 10 for 5‐kHz NB and L ∼ 4 to 7 for 20‐kHz NB. In many cases, Cassini passes through the source region of the 20‐kHz NB, as indicated by intense electrostatic upper hybrid (ESUH) waves in close proximity to electromagnetic emissions on spectrograms. The positions of the spacecraft when intense ESUH waves are observed agree with the model predictions of the NB source locations. Source locations determined by goniopolarimetric (also known as direction‐finding) analysis of the NB emissions also support the above results, although sometimes the directions of arrival point toward the region interior to Saturn's plasma torus. A polarization reversal technique is applied to localize the NB emissions observed during spacecraft rotation, on the basis of the fact that the source is within the antenna plane when the apparent circular polarization degree switches sign. The NB emissions are found to be L‐O mode polarized, which is consistent with the prediction of linear/nonlinear mode conversion theory. It is also found that sometimes right‐hand polarized NB emissions are generated at second harmonic frequencies of the 20‐kHz NB; in which case, wave‐wave interactions between oppositely propagating ESUH waves may play an important role in the mode conversion process.

Promises of Peace and Passion: Enthusing the Readers of Self-Help

Promises of Peace and Passion: Enthusing the Readers of Self-Help

Allan Kaufman's contributions to plasma wave theory

A brief review is presented of the contributions of Allan Kaufman to the theory of plasma waves. These contributions have been rich and various, characterized by high quality and a sense of what makes a problem both interesting and important. We include a brief summary of work prior to the mid-1980's, but the primary emphasis will be on more recent work concerning the use of phase space methods in the theory of linear plasma waves and mode conversion. One goal of the paper is to place Allan's contributions in the wider context of semi-classical methods. We will emphasize the underlying intuitions rather than providing a detailed mathematical exposition which can be found in the literature cited.

Dialectical Displacement and Redeployment of Attachments in the Kenotic Mode of Conversion: The Leaving Behind of Anton Boisen in Psychosis

This paper introduces a kenotic theory of conversion that builds from simple attachment to childhood experience of peak states to encompass dialectical stages of development: Priming, Decentering, Reflection, Encounter, Denucleation, Emplacement and Discipline. Thereafter, the dialectical mode gives rise to the mature phase of conversion—the continuing integration of the religious worldview through Metamorphosis and Embassy. The conversion theory is illustrated by an interpretation of a dialectical set of experiences of Anton Boisen. I interpret Anton Boisen’s conversion from a 19th Century Christianity that was wedded to religious and racial manifest destiny to that of a reborn Christian living with the 20th Century’s experience of evangelical and evolutionary universalism. Boisen’s clinical desolations (“psychosis”) and adoption of vocation (“change of allegiance”) suggest his conversion counterposed the instinctual with the higher order ideals he struggled to embody—a dialectical negation of his younger static and triumphalist Christian cultural identity that developed into a more integrated, expansive, and inclusive view of the human family and deepening allegiance to the ordinary, underserved, and growing population of the mentally suffering.

Pathways to Druidry: A Case Study of Ár nDraíocht Féin

Contemporary Druidry is a religious expression that claims ties to the ancient Druids of Indo-European origin. These ties are not necessarily historical as much as they are ideological. As one expression of this form of Druidry, Ár nDraíocht Féin (ADF) represents a vital and growing new religious movement in the United States and Western Europe. The question arises as to how people encounter ADF and what leads them to become adherents. This article analyzes field data to build a framework for understanding the various pathways to ADF. Utilizing the Lofland-Stark model of conversion, the article discusses conversion theory in light of the testimonies of adherents to ADF. The article concludes by suggesting that religious deprivation, religious identity, and religious legitimacy are factors that contribute to conversion and should be a focus of study in conversion theory.

An introduction to the quantum theory of nonlinear optics

An introduction to the quantum theory of nonlinear opticsThis article is provides an introduction to the quantum theory of optics in nonlinear dielectric media. We begin with a short summary of the classical theory of nonlinear optics, that is nonlinear optics done with classical fields. We then discuss the canonical formalism for fields and its quantization. This is applied to quantizing the electromagnetic field in free space. The definition of a nonclassical state of the electromagnetic field is presented, and several examples are examined. This is followed by a brief introduction to entanglement in the context of field modes. The next task is the quantization of the electromagnetic field in an inhomogeneous, linear dielectric medium. Before going on to field quantization in nonlinear media, we discuss a number of commonly employed phenomenological models for quantum nonlinear optical processes. We then quantize the field in both nondispersive and dispersive nonlinear media. Flaws in the most commonly used methods of accomplishing this task are pointed out and discussed. Once the quantization has been completed, it is used to study a multimode theory of parametric down conversion and the propagation of quantum solitons.