This thesis seeks to research patterns of economic growth and development from a number of perspectives often resonated in the growth literature. By addressing themes about history, geography, institutions and culture the thesis is able to bring to bear a wide range of inter-related literatures and methodologies within a single content. Additionally, by targeting different administrative levels in its research design and approach, this thesis is also able to provide a comprehensive treatment of the economic growth dilemma from both cross-national and sub-national perspectives. The three chapters herein discuss economic development from two broad dimensions. The first of these chapters takes on the economic growth inquiry by attempting to incorporate cultural geography within a cross-country formal spatial econometric growth framework. By introducing the global cultural dynamics of languages and ethnic groups as spatial network mechanisms, this chapter is able to distinguish economic growth effects accruing from own-country productive efforts from those accruing from interconnections within a global productive network chain. From this, discussions and deductions about the implications for both developed and developing countries are made as regards potentials for gains and losses from such types and levels of productive integration. The second and third chapters take a different spin to the economic development inquiry. They both focus on economic activity in Africa, tackling the relevant issues from a geo-intersected dimension involving historic regional tribal homelands and modern national and subnational administrative territories. The second chapter specifically focuses on attempting to adopt historical channels to investigate the connection between national institutional quality and economic development in demarcated tribal homelands at the fringes of national African borders. The third chapter on the other hand focuses on looking closer at the effects of demarcations on economic activity. It particularly probes how different kinds of demarcation warranted by two different but very relevant classes of politico-economic players have affected economic activity quite distinguishably within the resulting subnational regions in Africa.

ABSTRACT The radiographers experience of working in a trauma-team during a CT-trauma examination An interview study Background: Computed Tomography (CT) in trauma is a recurring examination that the radiographers must perform often under time pressure. Part of the radiographer’s skills are good collaboration and communication with various professions during handling of trauma. Many studies conclude that communication is a recurring problem in emergency team. Objective: The aim of this interview study is to examine the radiographers experience of their work in an emergency team. Method: The study was conducted as a qualitative interview study where semi-structured interviews were the basis. Content analysis according to Graneheim & Lundman (2012) was used in the study where an objective analysis based on the respondents' narratives about their experiences within the trauma team was performed. Five radiographers in a midsize hospital with CT modality and an emergency team and which also had at least two years’ experience in CT-trauma examination were included in this study. Results: Four categories were identified such as streamlining work, belonging to an emergency team, communication, the radiographers in a trauma environment. Based on four subcategories, four subcategories were developed. Various experiences were captured in the interviews and provided a meaningful analysis. The radiographer’s experienced exclusion and sense of being forgotten within the emergency team work. Even lack of internal and external communication was experienced by some radiographers. However, a licensed radiographer has responsibility to keep up a good communication with other professions within the emergency team. Conclusion: While some radiographers experienced being left out from the work with the emergency team, others experienced inclusion. The common goal of all the involved professions is to conduct an urgent examination with diagnostic quality in a short time frame. Improvements in the workflow were possible through planning and preparation. Various obstacles in the workflow could be remedied by the radiographers. Keywords: CT trauma, Radiography, Computed Tomography

Silicon Carbide as a wide-bandgap semiconductor has several physical and electrical advantages over Silicon for high voltage and high frequency applications. SiC as a MOSFET device has a lot of great characteristics like lower on-resistance and low input capacitances. However, due to its high switching capabilities, SiC MOSFET-based converter circuits experience higher dv/dt and di/dt transients and are therefore more susceptible to parasitic elements. This thesis investigates the interaction of the parasitic gate inductance and resistance on the switching behaviour of SiC DMOSFET (planar) and UMOSFET (trench). To examine this, a double pulse test (DPT) setup was utilised both in simulation and experimentally. The influence of the gate inductance and resistance on the oscillation behaviour in the VGS during the miller period was found to be dependent on the condition of the upper device. Furthermore, the upper device was discovered to have a high impact on the oscillations in the VGS via its source inductance. The gate inductance showed a mixed impact on IDS and VDS overshoot, with IDS overshoot reducing with increasing gate inductance and the reverse case for VDS. The gate resistance, however, showed a consistent impact on both IDS and VDS overshoot, with both reducing with increasing gate resistance. These results ultimately point to the impact of di/dt and dv/dt transients. An interesting result observed on these root causes showed that in the DPT arrangement used, lower test current levels may have a more significant impact on the oscillations in the VGS than higher test current when varying the test currents, with 20 A having the highest impact on the oscillations in simulations and 15 A having the highest impact in experimental verification. On the switching energy, the gate inductance was not shown to have a significant impact on switching losses while the gate resistance had a much more significant impact on the switching losses. / Kiselkarbid som halvledare med brett bandgap har flera fysiska och elektriska fördelar jämfört med kisel för högspännings- och högfrekvensapplikationer. SiC som en MOSFET-enhet har många fantastiska egenskaper som lägre resistans och låga ingångskapacitanser. Men på grund av dess höga omkopplingsförmåga upplever SiC MOSFET-baserade omvandlarkretsar högre dv/dt och di/dt transienter och är därför mer mottagliga för parasitiska element. Denna avhandling undersöker interaktionen mellan gate-drivkretsens parasitära induktans och resistans på kopplingsbeteendet på SiC DMOSFET (plan) och UMOSFET (trench). För att undersöka detta användes en dubbelpulstest (DPT) mätuppställning både i simulering och experimentellt. Inverkan av grindinduktansen och motståndet på svängningsbeteendet i VGS under Millerperioden visade sig vara beroende av den övre anordningens tillstånd. Vidare upptäcktes att den övre anordningen hade en hög inverkan på svängningarna i VGS via dess parasitiska induktans. Gate-induktansen visade en blandad inverkan på IDS- och VDS-översvängning, med IDS-översvängning som minskade med ökande gateinduktans och det omvända fallet för VDS. Gatemotståndet visade dock en konsekvent inverkan på både IDS- och VDS-överskridningar, med båda minskande med ökande gatemotstånd. Dessa resultat pekar slutligen på inverkan av di/dt- och dv/dt-transienter. Ett intressant resultat som observerats på dessa grundorsaker visade att i det använda DPT-arrangemanget kan lägre testströmnivåer ha mer signifikant inverkan på svängningarna i VGS än högre testström vid variation av testströmmarna, med 20 A som har den högsta inverkan på svängningarna i simuleringar och 15 A som har störst effekt vid experimentell verifiering. På omkopplingsenergin visades inte grindinduktansen ha någon signifikant inverkan på omkopplingsförlusterna medan grindresistansen hade mycket mer betydande inverkan på omkopplingsförlusterna.

No description available.

With the development and use of Silicon-Carbide [Silicon-Carbide (SiC)] devices come a host of advantages, including higher switching frequency, improved thermal performance, and higher voltage rating. This higher switching frequency can reduce the size of the con- verter system, but is typically associated with higher dv/dt voltage slew rates that further increase electromagnetic interference (EMI) related phenomena. Conventional gate-drivers are very limited in the way that they can control this high dv/dt, and this leads to the use of active gate-drivers. This thesis will explore the use of an active voltage-controlled gate-driver for SiC devices, utilizing transiently a voltage closer to the Miller plateau than the nominal turn-on and turn-off voltage to introduce control over the switching transient. Various ap- plied voltages, and voltage sequences will be evaluated to determine their effectiveness for controlling dv/dt and their impact on switching loss. Through this work, a better under- standing of the advantages and drawbacks of an active gate-driver can be found. The main result from this work is the effective reduction in the dv/dt generated by MOSFET devices, which was attained at a lower switching loss penalty compared to conventional resistive gate-drivers operating at similar dv/dt rates. Simulation and experimental results obtained with a prototype active gate-driver circuitry were used for this evaluation. / Master of Science / Within power electronic systems such as an inverter used to connect solar panels to the grid, are electrically controlled switches. These switches traditionally have been made of Silicon (Si) which imposed limitations on how fast they could transition from off to on, and vice versa, they also could only switch a relatively small number of times per second. However, a new generation of devices made from a silicon carbide material are being increasingly adopted, some key advantages of these new devices include much higher number of times to switch per second, and faster transitions from off-on and on-off. The trade-off that comes with this faster operation is an increase in the electromagnetic noise generated by these switches, among other issues. This work looks to explore a more unique method of controlling the turn-on and turn-off of these new switches and evaluating its impact on the noise generated and the losses during switching.

Inklusion von Menschen mit Behinderungen ist zu einem der vordringlichen Ziele der Sozialpolitik der Europäischen Union und in der Russischen Föderation geworden, u. a. aufgrund der zunehmenden Zahl von Ländern, die die UN-BRK1 ratifizierten, sowie Herausforderungen wegen, die eine "alternde" Gesellschaft verursacht. Jedoch werden Menschen mit Hörbehinderung und deren spezielle Bedürfnisse im Vergleich zu anderen, eher sichtbaren Behinderungen, oft übersehen. Das zentrale Anliegen der vorliegenden Untersuchung ist es, die Mechanismen und Ergebnisse der sozialen Inklusion schwerhöriger Menschen in Russland und Deutschland näher zu betrachten und zu vergleichen, sowie mit empirisch belegten Befunden zur Forschung über schwerhörige Personen beizutragen. Der Forschungstand hierzu ist in den Disability Studies noch sehr lückenhaft. Eine Analyse der Sozial- und Behindertenpolitik in beiden Ländern sowie ein Vergleich der rechtlichen und institutionellen Maßnahmen als auch der Chancen bildet den Rahmen für eine empirische Analyse (Fragebogen, Interviews mit schwerhörigen Personen, NGOs und Experten). Die Einschätzung der politischen Maßnahmen und der Infrastrukturen folgt den konzeptionellen und normativen Bewertungsmaßstäben der Disability Studies. Die vergleichende Analyse konzentriert sich auf den Zugang schwerhöriger Menschen zu Bildung und Arbeitsmarkt, zu Wiedereingliederung, Information und Kommunikation – Bereiche welche für Inklusion und Teilhabe entscheidend sind. Die empirischen Erhebungen enthalten explorative, nicht-repräsentative Fragebögen-Untersuchungen unter a) 190 jungen Befragten, 18-35 Jahre alt (davon 136 aus Deutschland; 150 aus Russland) b) 110 älteren Befragten, 65 bzw. 60 Jahre alt — abhängig vom betreffenden Land — und älter (43 aus Deutschland; 67 aus Russland) und Experten-Interviews mit Schlüsselpersonen zum Thema (Forscher, politische Entscheidungsträger, medizinische und pädagogische Experten, schwerhörige NGO-Aktivisten); darüber hinaus Leitfaden-Interviews mit schwerhörigen Personen (11 in Deutschland, 16 in Russland). Übereinstimmungen und Abweichungen in den nationalen politischen Richtlinien werden diskutiert, Beispiele von positiven Praktiken in medizinischer, ausbildungsbezogener und beruflicher Rehabilitation und potentielle politische Maßnahmen werden vorgeschlagen. / Inclusion of people with disabilities has become one of the priorities of the social policy in the European Union and in the Russian Federation, in part, in connection with the increasing ratification of the UN CRPD worldwide and problems induced by the “ageing” society. However, people with hearing loss and their specific needs are often overlooked in comparison with more visible disabilities. The main purpose of this study is to look into and compare the mechanisms and results of social inclusion of hard of hearing people (HoH) in Russia and Germany and to contribute with empirically grounded findings to the research on hard of hearing people of which there is a lack in the disability research field. An analysis of the social and disability related policies in both countries and a comparison of the legal and institutional arrangements and opportunities provides the framework for the empirical analysis (questionnaire, interviews with HoH persons, NGOs and with experts). The appraisal of the policies and infrastructures is following the conceptual and normative benchmarks of the Disability studies. The comparative analysis is focused on access of HoH people to education and employment, to rehabilitation, information and communication – the fields critical to inclusion and participation. The empirical research comprises an explorative non-representative questionnaire survey with a) 190 young respondents aged 18-35 years (136 from Germany, 150 from Russia) b) 110 elderly respondents (65 or 60 years old and older; 43 from Germany, 67 from Russia), and expert interviews with the key persons in the field (researchers, political decision-makers, medical and educational professionals, hard of hearing NGO activists); furthermore, guided interviews with HoH people (N=11 in Germany, N=16 in Russia) were conducted. Commonalities and discrepancies in the national policy directions are discussed, examples of positive practices in medical, educational and professional rehabilitation and potential policy measures are suggested.

Reliability is one of the important issues of recent microprocessor design. Processors must provide correct behavior as users expect, and must not fail at any time. However, unreliable operation can be caused by excessive supply voltage fluctuations due to an inductive part in a microprocessor power distribution network. This voltage fluctuation issue is referred to as inductive or di/dt noise, and requires thorough analysis and sophisticated design solutions. This dissertation proposes an automated stressmark generation framework to characterize di/dt noise effect, and suggests a practical solution for management of di/dt effects while achieving performance and energy goals. First, the di/dt noise issue is analyzed from theory to a practical view. Inductance is a parasitic part in power distribution network for microprocessor, and its characteristics such as resonant frequencies are reviewed. Then, it is shown that supply voltage fluctuation from resonant behavior is much harmful than single event voltage fluctuations. Voltage fluctuations caused by standard benchmarks such as SPEC CPU2006, PARSEC, Linpack, etc. are studied. Next, an AUtomated DI/dT stressmark generation framework, referred to as AUDIT, is proposed to identify maximum voltage droop in a microprocessor power distribution network. The di/dt stressmark generated from AUDIT framework is an instruction sequence, which draws periodic high and low current pulses that maximize voltage fluctuations including voltage droops. AUDIT uses a Genetic Algorithm in scheduling and optimizing candidate instruction sequences to create a maximum voltage droop. In addition, AUDIT provides with both simulation and hardware measurement methods for finding maximum voltage droops in different design and verification stages of a processor. Failure points in hardware due to voltage droops are analyzed. Finally, a hardware technique, floating-point (FP) issue throttling, is examined, which provides a reduction in worst case voltage droop. This dissertation shows the impact of floating point throttling on voltage droop, and translates this reduction in voltage droop to an increase in operating frequency because additional guardband is no longer required to guard against droops resulting from heavy floating point usage. This dissertation presents two techniques to dynamically determine when to tradeoff FP throughput for reduced voltage margin and increased frequency. These techniques can work in software level without any modification of existing hardware. / text

Submitted by Luciana Sebin (lusebin@ufscar.br) on 2016-10-06T13:19:49Z No. of bitstreams: 1 DissAOS.pdf: 12231590 bytes, checksum: 0d013d4adc46d9e7c5828719c8c6951f (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:24:59Z (GMT) No. of bitstreams: 1 DissAOS.pdf: 12231590 bytes, checksum: 0d013d4adc46d9e7c5828719c8c6951f (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:25:09Z (GMT) No. of bitstreams: 1 DissAOS.pdf: 12231590 bytes, checksum: 0d013d4adc46d9e7c5828719c8c6951f (MD5) / Made available in DSpace on 2016-10-13T20:25:19Z (GMT). No. of bitstreams: 1 DissAOS.pdf: 12231590 bytes, checksum: 0d013d4adc46d9e7c5828719c8c6951f (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Mammography is considered the “gold standard"in the early detection of breast cancer, being this disease one of the greatest health problems of women worldwide. Clustered microcalcifications detected on mammograms are very important findings in asymptomatic patients with early breast cancer and may be considered one of the first signs of malignancy. However, due to the small size of these structures, associated with the visual fatigue of radiologists resulting from the analysis of a large volume of images, clinical studies indicate that from 10 to 30% of microcalcifications presented in mammograms are lost during diagnosis. Within this scenario, this master thesis aims to develop an automatic system for the detection of clustered microcalcifications in digitized mammography images. To solve this problem, we use the transformed dua-three complex wavelet to detect the microcalsifications since this technique has some important characteristics for the signal analysis, for instance, good directional selectivity, approximate shift invariance and it provides both information - magnitude and phase. After the detection of isolated microcalcifications, a post-processing step is used to automatically demarcate regions containing clusters of microcalcifications. Furthermore, three techniques were investigated for the analysis of each clustered detection in order to identify false-positive clusters, such as: the Hessian matrix, the groups exclusion and the gray level co-occurrence matrix technique and SVM classifiers. For the development and testing of the algorithms one digitized mammogram database were used. The analysis of the results were performed by using ROC and FROC curves. The method achieved good results when compared to the mark made by experts. / A mamografia é considerada o "padrão ouro"na detecção precoce do câncer de mama, sendo essa doença um dos maiores problemas de saúde da mulher no mundo. Agrupamentos de microcalcificações detectados nos mamogramas são achados muito importantes em pacientes assintomáticas com câncer de mama e podem representar o primeiro sinal de malignidade. No entanto, devido ao reduzido tamanho dessas estruturas, associado à fadiga visual dos radiologistas resultante da análise de grandes volumes de imagens, estudos clínicos indicam que de 10 a 30% das microcalcificações presentes nos mamogramas são perdidas durante o diagnóstico. Diante deste quadro, este trabalho de mestrado tem por objetivo o desenvolvimento de um sistema automático para a detecção de agrupamentos de microcalcificações em imagens de mamogramas digitalizados. Para isso, utilizou-se a transformada wavelet complexa de árvore dupla (DT-CWT) para a detecção das microcalcificações, visto que essa técnica possui características importantes para a análise de sinais como, por exemplo, boa seletividade direcional, invariância aproximada ao deslocamento e fornece ambas informações – magnitude e fase. Após a detecção das microcalcificações isoladas, uma etapa de pós-processamento foi utilizada para demarcar automaticamente regiões contendo agrupamentos de microcalcificações. Além disso, três técnicas foram investigadas para a análise de cada agrupamento detectado, com o intuito de identificar agrupamentos falsopositivos, sendo elas: a matriz Hessiana, a exclusão de agrupamentos e a técnica de matriz de coocorrência de níveis de cinza e classificadores SVMs. Uma base de dados de mamogramas digitalizados foi utilizada para o desenvolvimento e testes dos algoritmos. A análise dos resultados foi realizada usando curvas ROC e FROC. O método obteve bons resultados quando comparado às marcações realizadas por especialistas e presentes na base de dados.

Digital Twins (DTs) are nowadays gaining popularity as time-to-market is becoming a crucial factor to a product success. A twin replicates the behavior of a physical system in a virtual environment and the added value it provides depends on its accuracy and simulation time. In fact, a twin can be used to simulate corner cases in which damage can occur to the real system, or to run parallel tests to accelerate the development process. This work presents a DT for the VL53L0X Time-of-Flight (ToF) sensor developed with SystemC/Transaction Level Modeling (TLM)-2.0 standard. A generic method is introduced to investigate the minimal descriptive parameters to build empirical sensor models, in addition to how the use of different synchronization methods would affect the accuracy and simulation time of such sensors. The digital interface that connects the sensor to the Microcontroller Unit (MCU) has been developed using the sensor datasheet to mimic the Inter-Integrated Circuit (I2C) protocol. Results show that the real distance (measured by ray tracing in the simulator), the reflectance and the ambient light intensity can be used to mimic the output registers of the sensor. Furthermore, interpolating the fitting parameters can yield to results similar to that of a lookup method if the interpolation interval is small enough. The model has been integrated in two different co-simulations using different mechanical simulators with a plug-and-simulate easy-to-use Transmission Control Protocol (TCP) interface. The simulation time depends on the synchronization method used but no separability has been determined between the mechanical simulator and the TCP overhead. / Digitala tvillingar (DT) är idag alltmer populära eftersom time-to-market blir en avgörande faktor för en produkts framgång. En tvilling återskapar beteendet hos ett fysiskt system i en virtuell miljö och det mervärde den ger beror på dess noggrannhet och simuleringstid. En tvilling kan användas för att simulera hörnfall där skador kan uppstå på det verkliga systemet, eller för att köra parallella tester för att påskynda utvecklingsprocessen. Detta arbete presenterar en DT för VL53L0X ToF-sensorn som utvecklats med SystemC/TLM-2.0 standard. En generisk metod introduceras introduceras för att undersöka de minimala beskrivande parametrarna för att bygga empiriska sensor sensormodeller, utöver hur användningen av olika synkroniseringsmetoder skulle påverka noggrannheten och simuleringstiden för sådana sensorer? Det digitala gränssnittet som ansluter sensorn till mikrokontrollerenheten har utvecklats med hjälp av sensorns datablad för att efterlikna I2C-protokollet. Resultaten visar att det verkliga avståndet (uppmätt med strålspårning i simulatorn), reflektansen och den omgivande ljusintensiteten kan användas för att efterlikna sensorns utgångsregister. Dessutom kan interpolering av anpassningsparametrarna ge resultat som liknar dem från en uppslagsmetod om interpoleringsintervallet är tillräckligt litet. Modellen har integrerats i två olika samsimuleringar med hjälp av olika mekaniska simulatorer med ett lättanvänt TCP-gränssnitt för plug-and-simulate. Simuleringstiden berodde på vilken synkroniseringsmetod som användes, men ingen separerbarhet har fastställts mellan den mekaniska simulatorn och TCP overhead-gränssnittet.

In der Arbeit wird die Lesekompetenz von SchülerInnen in Hörgeschädigtenschulen untersucht. Es werden Verfahren genutzt, die im Rahmen der aktuellen Bildungsevaluation nach der PISA- und IGLU-Studie zum Einsatz kommen. In den drei durchgeführten Teiluntersuchungen ist die Klasse des Berliner Schulversuchs als Beispiel eines bilingualen (d. h. gebärden-, laut- und schriftsprachlichen Unterrichts) beteiligt: a) 49 hörgeschädigte ViertklässlerInnen werden mit Hilfe einer IGLU-Textaufgabe untersucht. b) Es wird die VERA-Deutscharbeit 2005 von 57 hörgeschädigten ViertklässlerInnen evaluiert. c) Eine schulweite Studie zur Lesekompetenz an der Ernst-Adolf-Eschke-Schule wird vorgestellt, in der 34 zumeist hochgradig hörgeschädigte Viert- bis NeuntklässlerInnen unter identischen Bedingungen (mit der VERA-Deutscharbeit 2005) evaluiert werden. Eine auf nationalen und internationalen Vorstudien basierende forschungsleitende Hypothese bestätigt sich: Bei gehörlosen und schwerhörigen SchülerInnen in einem weitgehend lautsprachlichen Unterricht findet sich ein Zusammenhang zwischen Hörstatus und Schriftsprachkompetenz. In einem bilingualen Konzept, das für alle SchülerInnen eine funktionale Basissprache zur Verfügung stellt, ist dieser Zusammenhang nicht gegeben oder wird abgeschwächt. So übertrifft die bilinguale vierte Klasse in der schulweiten Untersuchung alle anderen Gruppen, bis hin zur neunten Klasse. Die bilingualen SchülerInnen haben ein entwickeltes diskursstrukturelles Verständnis, exekutives Metawissen und zeigen flexible Schriftspracherwerbsverläufe. Insgesamt liegen die Ergebnisse der hörgeschädigten SchülerInnen unter der hörenden Altersnorm, wobei sich die Variable eines nicht-deutschsprachigen Elternhauses bzw. Migrationshintergrundes als weiteres entscheidendes Merkmal erweist, das sich belastend auf die Entwicklung der Lesekompetenz auswirkt, und SchülerInnen mit einem CI in den beteiligten Hörgeschädigtenklassen überwiegend schwache Ergebnisse erzielen. / The research project focuses on reading literacy in students in schools for the deaf and hard-of- hearing. Research methods are based on current evaluation programs in educational science, following the example of the PISA and IGLU (international name: PIRLS) studies. Three smaller studies are presented, each of which includes a bilingual trial class at the Berlin School for the Deaf, where deaf students are educated by means of sign, spoken, and written language combined: a) 49 hearing impaired fourth graders are evaluated with the help of an IGLU-task. b) A nationwide German test (VERA-Deutscharbeit 2005) of 57 hearing impaired fourth graders is examined. c) At the Berlin School for the Deaf 34 mostly deaf fourth to ninth graders are tested under identical conditions (using the VERA-Deutscharbeit 2005). The results support findings indicated by previous national and international studies: in an educational environment where spoken language is the main means of instruction hearing loss is an important predictor for low literacy. In a bilingual class all students have access to at least one language. Here, the influence of hearing loss as a predictor is weakened or vanishes. The bilingual fourth graders show better results than any other class of their school including ninth graders. They have a higher understanding of the structures of discourse, more highly developed meta-cognitive skills and show flexible ways in the acquisition of written language. The overall results of the deaf and hard-of-hearing students are significantly below the hearing age norm. Deaf and hard-of-hearing students with non-German speaking parents show lower results than those with German-speaking parents. Within this study the majority of children with cochlear-implants produces very weak results.