System for studies of control strategies applied in the refrigerated chambers

The process of cold storage chambers contributes largely to the quality and longevity of stored products. In recent years, it has been intensified the study of control strategies in order to decrease the temperature change inside the storage chamber and to reduce the electric power consumption. This study has developed a system for data acquisition and process control, in LabVIEW language, to be applied in the cooling system of a refrigerating chamber of 30m³. The use of instrumentation and the application developed fostered the development of scientific experiments, which aimed to study the dynamic behavior of the refrigeration system, compare the performance of control strategies and the heat engine, even due to the controlled temperature, or to the electricity consumption. This system tested the strategies for on-off control, PID and fuzzy. Regarding power consumption, the fuzzy controller showed the best result, saving 10% when compared with other tested strategies.

Influence of distance, geometry and number of control stations on quality of local geodetic networks for the purpose of georeferencing of rural properties

The implementation of local geodetic networks for georeferencing of rural properties has become a requirement after publication of the Georeferencing Technical Standard by INCRA. According to this standard, the maximum distance of baselines to GNSS L1 receivers is of 20 km. Besides the length of the baseline, the geometry and the number of geodetic control stations are other factors to be considered in the implementation of geodetic networks. Thus, this research aimed to examine the influence of baseline lengths higher than the regulated limit of 20 km, the geometry and the number of control stations on quality of local geodetic networks for georeferencing, and also to demonstrate the importance of using specific tests to evaluate the solution of ambiguities and on the quality of the adjustment. The results indicated that the increasing number of control stations has improved the quality of the network, the geometry has not influenced on the quality and the baseline length has influenced on the quality; however, lengths higher than 20 km has not interrupted the implementation, with GPS L1 receiver, of the local geodetic network for the purpose of georeferencing. Also, the use of different statistical tests, both for the evaluation of the resolution of ambiguities and for the adjustment, have enabled greater clearness in analyzing the results, which allow that unsuitable observations may be eliminated.

Peter Pan never goes out of style : nuorisotutkijat ymmällään

Kirjallisuusarvostelu

Viitekehyksen kehitys, kehykseen perustuvat tutkimukset ja niiden anti : case: Levers of Control

Tutkielmassa tarkastellaan yrityksen strategian ja ohjauksen yhdistävän Levers of Control -viitekehyksen syntymistä ja kehittymistä nykyiseen muotoonsa. Lisäksi tutkimus perehtyy viitekehystä hyödyntävien tieteellisten tutkimusten antiin strategian ja ohjausjärjestelmien ymmärtämisessä sekä näiden tutkimusten antia itse viitekehykselle. Tutkielma on luonteeltaan käsiteanalyyttinen, analysoiden aiheesta julkaistua aikaisempaa kirjallisuutta. Kirjallisuus on rajattu viitekehyksen kehittäjän Robert Simonsin aiheesta kirjoittamaan materiaaliin sekä eri journaaleista löytyvään viitekehystä hyödyntävään aineistoon. Vaikka viitekehys on luotu myös käytännön toimijoiden avuksi, on tähän liittyvä aineisto kuitenkin rajattu tässä tutkielmassa pois tarkastelusta. Viitekehyksen kehityksen havaitaan noudattavan hermeneuttisen kehän piirteitä, sillä kehityksessä voidaan nähdä neljä erilaista vaihetta: esiymmärrys, esikehys, idea viitekehyksestä ja varsinaisen viitekehyksen vaihe. Kutakin näistä kehistä analysoidaan erikseen ja kaikkia vielä yhdessä. Havaitaan myös, että viitekehyksestä käyty vähäinen diskurssi on pääosin positiivista tunnustaen viitekehyksen ansiot mutta myös ongelmat myönnetään. Viitekehysanalyysin jälkeen siirrytään tarkastelemaan viitekehystä hyödyntävää materiaalia. Huomataan, että nämä tutkimusartikkelit voidaan luokitella neljään pääkategoriaan: empiriapohjaisiin, viitekehystä teoreettisesti hyödyntäviin, viitekehystä kehittämään pyrkiviin sekä opetustarkoituksessa kirjoitettuihin artikkeleihin. Näitä pääkategorioita analysoidaan usein eri tavoin erillisinä sekä yhtenä kokonaisuutena. Eri tutkimusartikkeleiden tuloksia on hankala kuitenkin yhdistää viitekehyksessä olevan ongelman takia: useimpien käytännön pohjalta luotujen selitysmallien tapaan Levers of Control –viitekehyksen käsitteet eivät ole yksiselitteisiä ja sama ongelma on nähtävissä myös viitekehystä hyödyntäneissä tutkimuksissa. Joitakin suuntaa antavia tuloksia interaktiivisuuden roolista ja dynaamisesta jännitteestä voidaan kuitenkin tehdä. Tiedeyhteisö ei ole hyväksynyt Levers of Control –viitekehystä varsinaiseksi teoriaksi. Tutkielmassa todetaan, että teoria-statuksen saaminen ei ole mahdotonta, mutta teoriaksi nousemiseen viitekehyksellä on kuitenkin vielä reilusti matkaa. Ennen sitä on havaitut ongelmat kyettävä ratkaisemaan ja löydettävä hyödyntämisen rajat. Ensimmäisiä askeleita tähän suuntaan ovat viitekehystä hyödyntämään pyrkivät tutkimusartikkelit pyrkineet jo kuitenkin ottamaan. Tutkielmassa tullaan siihen loppupäätelmään, että viitekehys on tällä hetkellä kehityskaarensa toisessa vaiheessa, sillä viitekehystä koskeva kirjoittelu keskittyy perustutkimukseen, arvolatautuneen kriittisen tutkimuksen puuttuessa vielä kokonaan.

Study of Control Methods of a High-Frequency Cycloconverter for Domestic Induction Heating Appliances

A high-frequency cyclonverter acts as a direct ac-to-ac power converter circuit that does not require a diode bidge rectifier. Bridgeless topology makes it possible to remove forward voltage drop losses that are present in a diode bridge. In addition, the on-state losses can be reduced to 1.5 times the on-state resistance of switches in half-bridge operation of the cycloconverter. A high-frequency cycloconverter is reviewed and the charging effect of the dc-capacitors in ``back-to-back'' or synchronous mode operation operation is analyzed. In addition, a control method is introduced for regulating dc-voltage of the ac-side capacitors in synchronous operation mode. The controller regulates the dc-capacitors and prevents switches from reaching overvoltage level. This can be accomplished by variating phase-shift between the upper and the lower gate signals. By adding phase-shift between the gate signal pairs, the charge stored in the energy storage capacitors can be discharged through the resonant load and substantially, the output resonant current amplitude can be improved. The above goals are analyzed and illustrated with simulation. Theory is supported with practical measurements where the proposed control method is implemented in an FPGA device and tested with a high-frequency cycloconverter using super-junction power MOSFETs as switching devices.

Fundraising and investor relations in social enterprise: Marketing your way out of the pioneer gap in African off-grid renewable energy

Social enterprises apply the best of business for the pursuit of social or environmental mission while also generating revenues. Globally, nearly 1,3 billion people lack access to electricity, as well as another billion having access to only low quality and infrequent electricity. Off-grid renewable energy, like solar, will increasingly have a key role in the solution of the energy access issue. The pioneer gap in off-grid renewable energy consists of financing (or funding) gaps and capacity gaps, to do with both the early stage of the enterprises in question, as well as the early stage of the whole industry. The gaps are emphasised by specific characteristics of off-grid renewable energy business models and the requirements of operating in bottom-of-the-pyramid markets. The marketing perspective to fundraising is chosen to uncover the possible role enterprises themselves have in bridging the pioneer gap. The purpose of this thesis is to study how social enterprises operating in off-grid renewable energy in Africa utilise marketing activities in their investor relations in bridging the pioneer gap. This main research question is divided into the following sub-questions:  How does the pioneer gap affect fundraising for these enterprises?  How are the funding needs for these enterprises characterised?  How do these enterprises build trust in their investor relations? The theoretic framework is built on relationship marketing and investor relations, with an emphasis on creation of trust. The research is conducted as a thematical case study. Primary data is gathered via semi-structured interviews with six solar energy companies and two accelerators. According to the findings, the main components affecting trust-creation are diminished information asymmetry and perceived risk, mission alignment as well as a personal fit or relationship with the investor. Therefore, an enterprise can utilise e.g. the following marketing activities in their investor relations to bridge the pioneer gap: ensuring investor material, the enterprise story and presenting of them is clear, concise and complete to “package” the enterprise as an investment; taking investor needs and motivations into account as well as utilising existing investors as ambassadors.

Dimensionality of the premenstrual syndrome: confirmatory factor analysis of premenstrual dysphoric symptoms among college students

Premenstrual syndrome and premenstrual dysphoric disorder (PMDD) seem to form a severity continuum with no clear-cut boundary. However, since the American Psychiatric Association proposed the research criteria for PMDD in 1994, there has been no agreement about the symptomatic constellation that constitutes this syndrome. The objective of the present study was to establish the core latent structure of PMDD symptoms in a non-clinical sample. Data concerning PMDD symptoms were obtained from 632 regularly menstruating college students (mean age 24.4 years, SD 5.9, range 17 to 49). For the first random half (N = 316), we performed principal component analysis (PCA) and for the remaining half (N = 316), we tested three theory-derived competing models of PMDD by confirmatory factor analysis. PCA allowed us to extract two correlated factors, i.e., dysphoric-somatic and behavioral-impairment factors. The two-dimensional latent model derived from PCA showed the best overall fit among three models tested by confirmatory factor analysis (c²53 = 64.39, P = 0.13; goodness-of-fit indices = 0.96; adjusted goodness-of-fit indices = 0.95; root mean square residual = 0.05; root mean square error of approximation = 0.03; 90%CI = 0.00 to 0.05; Akaike's information criterion = -41.61). The items "out of control" and "physical symptoms" loaded conspicuously on the first factor and "interpersonal impairment" loaded higher on the second factor. The construct validity for PMDD was accounted for by two highly correlated dimensions. These results support the argument for focusing on the core psychopathological dimension of PMDD in future studies.

Citizen Jane : exploring the relationship between gender and cellular phones in societies of control

In this thesis, I argue that the mutually productive relationship between women (as gendered subjects) and cellular phone technology is one of control. Women use cellular phones to organize, manage and otherwise control the multiplicity of tasks required of them on a daily basis. At the same time, through using cell phones, women participate in regimes of control including surveillance and persistent connection. I explore this relationship at the level of everyday practice, and conclude by speculating about this relationship at a wider level of social control and organization. This argument emerges from the critical approach suggested by Slack and Wise (2005), who argue that technology and culture are inseparable. They provide articulations and assemblages as tools of analysis. I situate this analysis more broadly within Foucault's (1991) work on govemmentality, in its modem form of societies of control (Deleuze, 1995b).

An empirical study of in-school and out-of-school day care

The purpose of this study was to determine if there were differences between in-school and out-of-school day care centres. Five centres housed in public schools and five housed in other locations were selected for the research. Aquality assessment was administered in each centre which examined the following components - physical environment, adult social structure and socia-emotional environment, children's socia-emotional environment, cognitive stimulation program and toys and equipment. Quantitative analysis using simple t-tests showed a significant difference between in-school and out-of-school day cares for the physical environment variable. Differences approached significance for the children's socia-emotional environment variable as well as overall quality. Qualitative analysis using a triangulated methodology revealed noticeable differences for every variable. The researcher concluded that both the quality of the physical environment and the capabilities of the administrators strongly influence the quality of the day care environment. This study also included an assessment of children's attitude toward learning. No significant difference was found between in-school and out-of-school centres.

An examination of the effects of locus of control on perceptions of core job dimensions and job satisfaction

This study examined the moderating effects of locus of control on core job dimensions (skill variety, task identity, task significance, autonomy, feedback) and job satisfaction. Survey data were collected from 1995 educators in Southern Ontario. When core job dimensions were perceived to be high, job satisfaction scores were high. The converse relationship was also true; when core job dimensions were perceived to be low, job satisfaction scores were also low. As well, the investigation explored the effect of educators' locus of control of reinforcement on the relationship between core job dimensions and job satisfaction. Internals (N = 483-486) perceived more skill variety, more task identity, more task significance, more autonomy, more feedback and greater job satisfaction than externals (N = 626-629). However, contrary to expectation, the correlations between specific core job dimensions namely autonomy and feedback, were not systematically greater for internals compared to externals. In addition the findings reported here suggest some appropriate directions and strategies for measuring and increasing job satisfaction among teachers.

Co-operative education and the development of self-esteem, an internal locus of control and work habits

This study compared approximately 50 grade 12 students studying In th~ co-operative education mode with approximately 50 grade 12 students studying in a traditional English course. Measures of self-esteem, locus of control and work habits were compared before and at the conclusion of one semester's involvement in the different programs. Using Coopersmith's Self-Esteem Inventory, the students who had chosen to study in the co-operative education mode scored significantly higher than the students in the traditional course. At the end of the semester, the co-operative education students' scores remained significantly higher than the English students'. Although the test showed no sjgnifi~ant changes in self-esteem. anecdotal reports indicated that co-operative education students had increased self-esteem over the semester. No significant differences in locus of control were observed between the two groups at any time. Significant differences in work habits were observed. While both groups had the same number of absences and the same marks before taking these courses, students who were involved in co-operative education had significantly fewer absences and significantly higher marks than the students studying in the traditional course. Anecdotal reports also indicated an improv~ment in work habits for students who had been involved in co-operative education. Recommendations of the study are for further research to determine more exactly how self-esteem and work habits develop in co-operative education students. Also. students. parents, teachers. and administrators need to be made aware of the success of this program.