With Good Reputation Size Does not Matter: Issue Frequency and the Determinants of Debt Maturity

This paper examines empirically the effect firm reputation has on the determinants of debt maturity. Utilising data from European primary bond market between 1999 and 2005, I find that the maturity choice of issuers with a higher reputation is less sensitive to macroeconomic conditions, market credit risk-premiums, prevailing firm credit quality and size of the debt issue. The annualised coupon payments are shown to be a significant factor in determining the debt maturity and reveal a monotonously increasing relationship between credit quality and debt maturity once controlled for. Finally, I show that issuers lacking a credit rating have an implied credit quality positioned between investment-grade and speculative-grade debt.

Grid interfacing of a photovoltaic system using a chain cell converter

With the rapid development of photovoltaic system installations and increased number of grid connected power systems, it has become imperative to develop an efficient grid interfacing instrumentation suitable for photovoltaic systems ensuring maximum power transfer. The losses in the power converter play an important role in the overall efficiency of a PV system. Chain cell converter is considered to be efficient as compared to PWM converters due to lower switching losses, modularized circuit layout, reduced voltage rating of the converter switches, reduced EMI. The structure of separate dc sources in chain cell converter is well suited for photovoltaic systems as there will b several separate PV modules in the PV array which can act as an individual dc source. In this work, a single phase multilevel chain cell converter is used to interface the photovoltaic array to a single phase grid at a frequency of 50Hz. Control algorithms are developed for efficient interfacing of the PV system with grid and isolating the PV system from grid under faulty conditions. Digital signal processor TMS320F 2812 is used to implement the control algorithms developed and for the generation of other control signals.

Vieraan aksentin arviointi ja mittaaminen suomessa

In the field of second language (L2) acquisition, the term `foreign accent´ is often used to refer to speech characteristics that differ from the pronunciation of native speakers. Foreign accent may affect the intelligibility and perceived comprehensibility of speech and it is also sometimes associated with negative attitudes. The degree of L2 learners foreign accent and the speech characteristics that account for it have previously been studied through speech perception experiments and acoustic measurements. Perception experiments have shown that native listeners are easily able to identify foreign accent in speech. However to date, no studies have been done on the assessment of foreign accent in the speech of non-native speakers of Finnish. The aim of this study is to examine how native speakers of Finnish rate the degree of foreign accentedness in the speech of Russian L2 learners of Finnish. Furthermore, phonetic analysis is used to study the characteristics of speech that affect the perceived strength of foreign accent. Altogether 96 native speakers of Finnish listened to excerpts of read-aloud and spontaneous Finnish speech from ten Russian and six Finnish female speakers. The Russian speakers were intermediate and advanced learners of Finnish and had all immigrated to Finland as adults. Among the listeners, was a group of teachers of Finnish as an L2, and it was presumed that these teachers had been exposed to foreign accent in Finnish and were used to hearing it. The temporal aspects and segmental properties of speech were phonetically analysed in the speech of the Russian speakers in order to measure their effect on the perceived degree of accent. Although wide differences were observed in the use of the rating scale among the listeners, they were still quite unanimous on which speakers had the strongest foreign accent and which had the mildest. The listeners background factors had little effect on their ratings, and the ratings of the teachers of Finnish as an L2 did not differ from those of the other listeners. However, a clear difference was noted in the ratings of the two types of stimuli used in the perception experiment: the read-aloud speech was rated as more strongly accented than the spontaneous speech. It is important to note that the assessment of foreign accent is affected by many factors and their complex interactions in the experimental setting. Futher the study found that, both the temporal aspects of speech, often associated with fluency, and the number of single deviant phonetic segments contributed to the perceived degree of accentedness in the speech of the native Russian speakers.

Choosing the Arranged One, Arranging the Chosen One – Imagining an Indian Modernity: Reconciling Love, Marriage and Family On and Off the Screen

This is a study on the changing practices of kinship in Northern India. The change in kinship arrangements, and particularly in intermarriage processes, is traced by analysing the reception of Hindi popular cinema. Films and their role and meaning in people´s lives in India was the object of my research. Films also provided me with a methodology for approaching my other subject-matters: family, marriage and love. Through my discussion of cultural change, the persistence of family as a core value and locus of identity, and the movie discourses depicting this dialogue, I have looked for a possibility of compromise and reconciliation in an Indian context. As the primary form of Indian public culture, cinema has the ability to take part in discourses about Indian identity and cultural change, and alleviate the conflicts that emerge within these discourses. Hindi popular films do this, I argue, by incorporating different familiar cultural narratives in a resourceful way, thus creating something new out of the old elements. The final word, however, is the one of the spectator. The “new” must come from within the culture. The Indian modernity must be imaginable and distinctively Indian. The social imagination is not a “Wild West” where new ideas enter the void and start living a life of their own. The way the young women in Dehra Dun interpreted family dramas and romantic movies highlights the importance of family and continuity in kinship arrangements. The institution of arranged marriage has changed its appearance and gained new alternative modes such as love cum arranged marriage. It nevertheless remains arranged by the parents. In my thesis I have offered a social description of a cultural reality in which movies act as a built-in part. Movies do not work as a distinct realm, but instead intertwine with the social realities of people as a part of a continuum. The social imagination is rooted in the everyday realities of people, as are the movies, in an ontological and categorical sense. According to my research, the links between imagination and social life were not so much what Arjun Appadurai would call global and deterritorialised, but instead local and conventional.

Pain measurement and management in elderly patients : Clinical studies in long term hospital care and after cardiac surgery

The proportion of patients over 75 years of age, receiving all different types of healthcare, is constantly increasing. The elderly undergo surgery and anaesthetic procedures more often than middle-aged patients. Poor pain management in the elderly is still an issue. Although the elderly consumes the greatest proportion of prescribed medicines in Western Europe, most clinical pharmacological studies have been performed in healthy volunteers or middle-aged patients. The aim of this study was to investigate pain measurement and management in cognitively impaired patients in long term hospital care and in cognitively normal elderly patients after cardiac surgery. This thesis incorporated 366 patients, including 86 home-dwelling or hospitalized elderly with chronic pain and 280 patients undergoing cardiac surgery with acute pain. The mean age of patients was 77 (SD ± 8) years and approximately 8400 pain measurements were performed with four pain scales: Verbal Rating Scale (VRS), the Visual Analogue Scale (VAS), the Red Wedge Scale (RWS), and the Facial Pain Scale (FPS). Cognitive function, depression, functional ability in daily life, postoperative sedation and postoperative confusion were assessed with MMSE, GDS, Barthel Index, RASS, and CAM-ICU, respectively. The effects and plasma concentrations of fentanyl and oxycodone were measured in elderly (≥ 75 years) and middle-aged patients (≤ 60 years) and the opioid-sparing effect of pregabalin was studied after cardiac surgery. The VRS pain scores after movement correlated with the Barthel Index. The VRS was most successful in the groups of demented patients (MMSE 17-23, 11-16 and ≤ 10) and in elderly patients on the first day after cardiac surgery. The elderly had a higher plasma concentration of fentanyl at the end of surgery than younger patients. The plasma concentrations of oxycodone were comparable between the groups. Pain intensity on the VRS was lower and the sedation scores were higher in the elderly. Total oxycodone consumption during five postoperative days was reduced by 48% and the CAM-ICU scores were higher on the first postoperative day in the pregabalin group. The incidence of postoperative pain during movement was lower in the pregabalin group three months after surgery. This investigation demonstrates that chronic pain did not seem to impair daily activities in home-dwelling Finnish elderly. The VRS appeared to be applicable for elderly patients with clear cognitive dysfunction (MMSE ≤17) and it was the most feasible pain scale for the early postoperative period after cardiac surgery. After cardiac surgery, plasma concentrations of fentanyl in elderly were elevated, although oxycodone concentrations were at similar level compared to middle-aged patients. The elderly had less pain and were more sedated after doses of oxycodone. Therefore, particular attention must be given to individual dosing of the opioids in elderly surgical patients, who often need a smaller amount for adequate analgesia than middle-aged patients. The administration of pregabalin reduced postoperative oxycodone consumption after cardiac surgery. Pregabalin-treated patients had less confusion, and additionally to less postoperative pain on the first postoperative day and during movement at three months post-surgery. Pregabalin might be a new alternative as analgesic for acute postoperative and chronic pain management in the elderly. Its clinical role and safety remains to be verified in large-scale randomized and controlled studies. In the future, many clinical trials in the older category of patients will be needed to facilitate improvements in health care methods.

Turvallinen koulu? : Helsinkiläisten peruskoulujen turvallisuuskulttuurista ja siihen vaikuttavista tekijöistä

Objectives. This study concentrated on the aspect of physical safety in the learning environment of primary and secondary schools in Helsinki. Taking a broad perspective, the study analysed the safety culture of Helsinki schools, ranked them with a point rating system, and thoroughly investigated reasons behind their differences. Safety culture in educa-tional institutions has not been studied previously although research related to safety culture in business is abundant and some studies have considered safety culture in the healthcare sector. The study focused on the attitudes and practices of teachers concerning safety. The main research question is as follows: "What factors related to safety culture distinguish schools with an exceptional safety culture from those weaker one?" Research methods. The study used a mixed-methods approach. It s quantitative part charted the safety attitudes, values and expertise of employees in selected schools. The study also analysed physical safety in selected schools through specific safety inspections. The 14 schools in the study were selected randomly, two from each district. Altogether 388 of 475 employees returned a Webropol questionnaire (N= 475, 81,68 %). The qualitative part of the study analysed the reasons behind perceived differences in school s safety cul-ture using theme interviews with school principals. Elements of a phenomenographic research approach were also used. Results and conclusions. According to the study the distinctive features of good safety cultures in the Helsinki schools included a well-developed understanding of safety hazards and the requirements of basic safety, good safety management practices, a developed understanding of the systematic nature of safety, an appreciation of safety evidenced through everyday practices and open and communal safety-related work. The study offers result-based safety culture improvements for teachers, those responsible for school safety, principals, educational administrators, teacher educators and authorities.

Essays on labour demand and wage formation

The first essay in this thesis is on gender wage differentials among manufacturing sector white-collar workers. The wage differential is decomposed into firm, job (within-firm) and individ-ual-level components. Job-level gender segregation explains over half of the gap, while firm-level segregation is not important. After controlling for firm, job and individual characteristics, the remaining unexplained wage cap to the advantage of men is six per cent of men s mean wage. In the second essay, I study how the business cycle and gender affect the distribution of the earnings losses of displaced workers. The negative effect of displacement is large, persistent and strongest in the lowest earnings deciles. The effect is larger in a recession than in a recov-ery period, and in all periods women s earnings drop more than men s earnings. The third essay shows that the transition from steady employment to disability pension de-pends on the stringency of medical screening and the degree of experience-rating of pension costs applied to the employer. The fact that firms have to bear part of the cost of employees disability pension costs lowers both the incidence of long sick leave periods and the probabil-ity that sick leave ends in a disability pension. The fourth and fifth essays are studies on the employment, wage and profit effects of a re-gional payroll tax cut experiment conducted in northern and eastern Finland. The results show no statistically significant effect on any of the response variables.

The Role of Electronic Word of Mouth in Shaping Consumer Attitudes

The purpose of this research was to investigate the role of electronic word of mouth (eWOM) in shaping consumer attitudes towards various products and services with concentration on the consumer attitude change. eWOM has long been proven to play an important role in influencing consumer attitudes and has been researched from a variety of perspectives. This study attempts to look deeper into the process of consumer attitude change by applying as the central theory of the study the Elaboration Likelihood Model of Persuasion by Petty and Cacioppo. In the processes of examining the background academic and empirical research the Internet and Web 2.0 are closely depicted in order to understand how throughout the past centuries technology allowed the rise of various mediums where consumers can not only share their opinions online about products and services but also communicate with other consumers. Manuel Castel’s Internet Galaxy, Gildin’s, Carl and Noland’s, Hennig-Thurau, Gwinner, Walsh and Gremler’s researches on eWOM are the central works that helped to shape both the theoretical and empirical parts of this study. The mixed method approach was chosen as a research method for this study. An online survey was conducted via the Surveymonkey.com platform and eight qualitative in-depth interviews were conducted. The results of the study show that central route queues as text quality and text argumentativeness are more prominent among the research subjects and the peripheral route queues: source credibility and source expertise did not show considerable significance. Also more experience and participation consumers have with user-rating websites and applications more inclined they are to elaborate on the central route cues and are more likely to search for opinions that they consider rational and credible. Also these respondents are less inclined to search for ratings that confirm their existing beliefs about products or services. Less experience/participation they have about eWOM more likely they are to search for reviews confirmatory to their own.

Five-level inverter scheme for an open-end winding induction machine with less number of switches

Higher level of inversion is achieved with a less number of switches in the proposed scheme. The scheme proposes a five-level inverter for an open-end winding induction motor which uses only two DC-link rectifiers of voltage rating of Vdc/4, a neutral-point clamped (NPC) three-level inverter and a two-level inverter. Even though the two-level inverter is connected to the high-voltage side, it is always in square-wave operation. Since the two-level inverter is not switching in a pulse width modulated fashion and the magnitude of switching transient is only half compared to the convention three-level NPC inverter, the switching losses and electromagnetic interference is not so high. The scheme is experimentally verified on a 2.5 kW induction machine.

Starting scheme for load commutated inverter-fed wound field synchronous machine using an auxiliary low-power voltage source inverter

Conventional thyristor-based load commutated inverter (LCI)-fed wound field synchronous machine operates only above a minimum speed that is necessary to develop enough back emf to ensure commutation. The drive is started and brought up to a speed of around 10-15% by a complex `dc link current pulsing' technique. During this process, the drive have problems such as pulsating torque, insufficient average starting torque, longer starting time, etc. In this regard a simple starting and low-speed operation scheme, by employing an auxiliary low-power voltage source inverter (VSI) between the LCI and the machine terminals, is presented in this study. The drive is started and brought up to a low speed of around 15% using the VSI alone with field oriented control. The complete control is then smoothly and dynamically transferred to the conventional LCI control. After the control transfer, the VSI is turned off and physically disconnected from the main circuit. The advantages of this scheme are smooth starting, complete control of torque and flux at starting and low speeds, less starting time, stable operation, etc. The voltage rating of the required VSI is very low of the order of 10-15%, whereas the current rating is dependent on the starting torque requirement of the load. The experimental results from a 15.8 hp LCI-fed wound field synchronous machine are given to demonstrate the scheme.

Variable-speed wind power generation using doubly fed wound rotor induction machine - A comparison with alternative schemes

In this paper, a wind energy conversion system (WECS) using grid-connected wound rotor induction machine controlled from the rotor side is compared with both fixed speed and variable speed systems using cage rotor induction machine. The comparison is done on the basis of (I) major hardware components required, (II) operating region, and (III) energy output due to a defined wind function using the characteristics of a practical wind turbine. Although a fixed speed system is more simple and reliable, it severely limits the energy output of a wind turbine. In case of variable speed systems, comparison shows that using a wound rotor induction machine of similar rating can significantly enhance energy capture. This comes about due to the ability to operate with rated torque even at supersynchronous speeds; power is then generated out of the rotor as well as the stator. Moreover, with rotor side control, the voltage rating of the power devices and dc bus capacitor bank is reduced. The size of the line side inductor also decreasesd. Results are presented to show the substantial advantages of the doubly fed system.

A Seven-Level Inverter Topology for Induction Motor Drive Using Two-Level Inverters and Floating Capacitor Fed H-Bridges

A multilevel inverter topology for seven-level space vector generation is proposed in this paper. In this topology, the seven-level structure is realized using two conventional two-level inverters and six capacitor-fed H-bridge cells. It needs only two isolated dc-voltage sources of voltage rating V(dc)/2 where V(dc) is the dc voltage magnitude required by the conventional neutral point clamped (NPC) seven-level topology. The proposed topology is capable of maintaining the H-bridge capacitor voltages at the required level of V(dc)/6 under all operating conditions, covering the entire linear modulation and overmodulation regions, by making use of the switching state redundancies. In the event of any switch failure in H-bridges, this inverter can operate in three-level mode, a feature that enhances the reliability of the drive system. The two-level inverters, which operate at a higher voltage level of V(dc)/2, switch less compared to the H-bridges, which operate at a lower voltage level of V(dc)/6, resulting in switching loss reduction. The experimental verification of the proposed topology is carried out for the entire modulation range, under steady state as well as transient conditions.

A Novel VSI- and CSI-Fed Active-Reactive Induction Motor Drive with Sinusoidal Voltages and Currents

Till date load-commutated inverter (LCI)-fed synchronous motor drive configuration is popular in high power applications (>10 MW). The leading power factor operation of synchronous motor by excitation control offers this simple and rugged drive structure. On the contrary, LCI-fed induction motor drive is absent as it always draws lagging power factor current. Therefore, complicated commutation circuit is required to switch off thyristors for a current source inverter (CSI)-driven induction motor. It poses the major hindrance to scale up the power rating of CSI-fed induction motor drive. Anew power topology for LCI-fed induction motor drive for medium-voltage drive application is proposed. A new induction machine (active-reactive induction machine) with two sets of three-phase winding is introduced as a drive motor. The proposed power configuration ensures sinusoidal voltage and current at the motor terminals. The total drive power is shared among a thyristor-based LCI, an insulated gate bipolar transistor (IGBT)-based two-level voltage source inverter (VSI), and a three-level VSI. The benefits of SCRs and IGBTs are explored in the proposed drive. Experimental results from a prototype drive verify the basic concepts of the drive.

High powerACmotor drives: Status review and work at IISc

A variety of solutions are available today from industry for high power variable speed AC motor drive applications, starting from a power rating of a few 100 kW to several 10’s of Megawatts. These drives can be classified on the basis of the electrical motor, the power converter and the control technique. The main drive types are reviewed.The salient features of each type of drive are pointed out along with their industrial applications.Following this, some research at IISc which has applications in high power drives is described briefly.

Space vector based bus clamped PWM algorithms for three level inverters: implementation, performance analysis and application considerations

This paper describes the different types of space vector based bus clamped PWM algorithms for three level inverters. A novel bus clamp PWM algorithm for low modulation indices region is also presented. The principles and switching sequences of all the types of bus clamped algorithms for high switching frequency are presented. Synchronized version of the PWM sequences for high power applications where switching frequency is low is also presented. The implementation details on DSP based digital controller and experimental results are presented. The THD of the output waveforms is studied for the entire operating region and is compared with the conventional space vector PWM technique. The bus clamped techniques can be used to reduce the switching losses or to improve the output voltage quality or both.. Different issues dominate depending on the type of application and power rating of the inverters. The results presented in this paper can be used for judicious use of the PWM techniques, which result in improved system efficiency and performance.