In this thesis, image dynamic range enhancement methods are studied in order to solve the problem of representing high dynamic range scenes with low dynamic range images. For this purpose, two main image dynamic range enhancement methods, which are high dynamic range imaging and exposure fusion, are studied. More detailed analysis of exposure fusion algorithms are carried out because the whole enhancement process in the exposure fusion is performed in low dynamic range, and they do not need any prior information about input images. In order to evaluate the performances of exposure fusion algorithms, both objective and subjective quality metrics are used. Moreover, the correlation between the objective quality metrics and subjective ratings is studied in the experiments.

The Hilbert space of probability mass functions (pmf) is introduced in this thesis. A factorization method for multivariate pmfs is proposed by using the tools provided by the Hilbert space of pmfs. The resulting factorization is special for two reasons. First, it reveals the algebraic relations between the involved random variables. Second, it determines the conditional independence relations between the random variables. Due to the first property of the resulting factorization, it can be shown that channel decoders can be employed in the solution of probabilistic inference problems other than decoding. This approach might lead to new probabilistic inference algorithms and new hardware options for the implementation of these algorithms. An example of new inference algorithms inspired by the idea of using channel decoder for other inference tasks is a multiple-input multiple-output (MIMO) detection algorithm which has a complexity of the square-root of the optimum MIMO detection algorithm. Keywords: The Hilbert space of pmfs, factorization of pmfs, probabilistic inference, MIMO detection, Markov random fields iv

Microwave limiting amplifiers are the key components of Instantaneous Frequency Measurement (IFM) systems. Limiting amplifiers provide constant output power level in a wide input dynamic range and over a broad frequency band. Moreover, limiting amplifiers are high gain devices that are used to bring very low input power levels to a constant output power level. Besides, limiting amplifiers are required to provide minimum small signal gain ripple in order not to reduce the sensitivity of the IFM system over the operating frequency band. In this thesis work, a high gain, medium power, 2-18 GHz limiting amplifier module is designed, simulated, fabricated and measured. First, a 3-stage cascaded amplifier with 27 dB small signal gain is designed and fabricated. The 3-stage amplifier is composed of a novel cascaded combination of negative feedback and distributed amplifiers that provides the minimum small signal gain ripple and satisfactory input and output return losses inside 2-18 GHz frequency band. Then, the designed two 3-stage amplifiers and one 4-stage amplifier are cascaded to constitute a limiting amplifier module with minimum 80 dB small signal gain. The designed 10-stage limiting amplifier module also includes an analog voltage controllable attenuator to be used for compensating the gain variations resulting from temperature changes. The fabricated 10-stage limiting amplifier module provides 20 +/- 1.2 dBm output power level and excellent small signal gain flatness, +/- 2.2 dB, over 2-18 GHz frequency range.

The terms &lsquo / ground-probing radar&rsquo / , &lsquo / ground penetrating radar (GPR)&rsquo / , &lsquo / sub-surface radar&rsquo / or &lsquo / surface-penetrating radar (SPR)&rsquo / refer to various techniques for detecting and imaging of subsurface objects. Among those terms GPR is preferred and used more often. In this thesis, the depth and the position of the buried circular cylinder are determined by a GPR system which comprises of an optical fiber sensor (OFS). The system is a combination of OFS, GPR and optical communication link. In order to determine the depth and the position, first of all the electric field distribution at the OFS is obtained by integrating the Green&rsquo / s function over the induced current distribution. Those distributions are observed for different frequency and depth values. The voltages inside the distribution are measured by OFS. By changing the depth of the cylinder and the frequency of the system, various plots showing x axis displacement versus measured voltages are obtained. Those plots are related to interference fringe patterns. The position and the depth of the cylinder are obtained using interference fringe patterns. All of the studies mentioned are performed in MATLAB R2007b program. The noises of the system due to OFS are extracted using OPTIWAVE OPTISYSTEM 7.0 program. By adding those noises to the measured voltage values, the operating frequency of the system is observed.

In this thesis, noncoherent differential demodulation of CPM signals with joint carrier frequency offset and symbol timing estimation is investigated. CPM is very attractive for wireless communications owing to major properties: good spectral efficiency and a constant envelope property. In order to demodulate the received CPM signal differentially, the symbol timing and the carrier frequency offset have to be estimated accurately. There are numerous methods developed for the purpose. However, we have not encountered studies (which are based on autocorrelation estimation and hence suitable for blind synchronization) that give expectable performance for both M-ary and partial response signaling. Thus, in this thesis we analyze a feedforward blind estimation scheme, which recovers the symbol timing and the frequency offset of M-ary CPM signals and partial response CPM signals. In addition, we surveyed low complexity symbol detection methods for CPM signals. Reduced state Viterbi differential detector incorporated to the joint frequency offset and symbol timing estimator is also examined. The performance of the examined demodulator scheme is assessed for the AWGN channel by computer simulations.

Higher Order Statistics (HOS) and Second Order Statistics (SOS) approaches have certain advantages and disadvantages in signal processing applications. HOS approach provides more statistical information for non-Gaussian signals. On the other hand, SOS approach is more robust to the estimation errors than the HOS approach, especially when the number of observations is small. In this thesis, HOS and SOS approaches are jointly used in order to take advantage of both methods. In this respect, the joint use of HOS and SOS approaches are introduced for online calibration of sensor arrays with arbitrary geometries. Three different problems in online array calibration are considered and new algorithms for each of these problems are proposed. In the first problem, the positions of the randomly deployed sensors are completely unknown except the two reference sensors and HOS and SOS approaches are used iteratively for the joint Direction of Arrival (DOA) and sensor position estimation. Iterative HOS-SOS algorithm (IHOSS) solves the ambiguity problem in sensor position estimation by observing the source signals at least in two different frequencies and hence it is applicable for wideband signals. The conditions on these frequencies are presented. IHOSS is the first algorithm in the literature which finds the DOA and sensor position estimations in case of randomly deployed sensors with unknown coordinates. In the second problem, narrowband signals are considered and it is assumed that the nominal sensor positions are known. Modified IHOSS (MIHOSS) algorithm uses the nominal sensor positions to solve the ambiguity problem in sensor position estimation. This algorithm can handle both small and large errors in sensor positions. The upper bound of perturbations for unambiguous sensor position estimation is presented. In the last problem, an online array calibration method is proposed for sensor arrays where the sensors have unknown gain/phase mismatches and mutual coupling coefficients. In this case, sensor positions are assumed to be known. The mutual coupling matrix is unstructured. The two reference sensors are assumed to be perfectly calibrated. IHOSS algorithm is adapted for online calibration and parameter estimation, and hence CIHOSS algorithm is obtained. While CIHOSS originates from IHOSS, it is fundamentally different in many aspects. CIHOSS uses multiple virtual ESPRIT structures and employs an alignment technique to order the elements of rows of the actual array steering matrix. In this thesis, a new cumulant matrix estimation technique is proposed for the HOS approach by converting the multi-source problem into a single source one. The proposed algorithms perform well even in the case of correlated source signals due to the effectiveness of the proposed cumulant matrix estimate. The iterative procedure in all the proposed algorithms is guaranteed to converge. Closed form expressions are derived for the deterministic Cram&acute / er-Rao bound (CRB) for DOA and unknown calibration parameters for non-circular complex Gaussian noise with unknown covariance matrix. Simulation results show that the performances of the proposed methods approach to the CRB for both DOA and unknown calibration parameter estimations for high SNR.

A fast and efficient method for the design of multi-layered circuit analog absorbing structures is developed. The method is based on optimization of specular reflection coefficient of a multi-layered absorbing structure comprising of lossy FSS layers by using Genetic Algorithm and circuit equivalent models of FSS layers. With the introduced method, two illustrative absorbing structures are designed with -15 dB reflectivity for normal incidence case in the frequency bands of 10-31 GHz and 5-46 GHz, respectively. To the author&rsquo / s knowledge, designed absorbers are superior in terms of frequency bandwidth to similar studies conducted so far in the literature. For broadband scattering characterization of periodic structures, numerical codes are developed. The introduced method is improved with the employment of developed FDTD codes to the proposed method. By taking the limitations regarding production facilities into consideration, a five-layered circuit analog absorber is designed and manufactured. It is shown that the manufactured structure is capable of 15 dB reflectivity minimization in a frequency band of 3.2-12 GHz for normal incidence case with an overall thickness of 14.2 mm.

¡mAbstract¡n This research examines six presses of Kaohsiung journalists', China Times, Liberty Times, United Daily News, Taiwan Times, Taiwan Shin Wen Daily News, and Public Daily News, the intra-organization media usage for Media Richness and Social Influence Model. It tests four media which are face to face, telephone, e-mail, and written document, and tests which one is suitable for Kaohsiung journalists use in formal communication and informal communication. The result is that the most journalist use face to face as their intra-organization media. Not only testing media usage, this research is also examining the prediction of media usage by Media Richness and Social Influence Model. The result is except downward communication media usage which lacks sufficient samples, the other communication flows' media usage prediction are Media Richness explanation of predicting media usage is better than Social Influence Model. For each press, face to face is the main choice for six presses' journalists in upward communication, horizontal communication and downward communication flow. However, United Daily News' journalists use written document as the main media in informal communication, but the other presses' still use face to face The finding in formal and upward communication, the prediction of media usage by Media Richness and Social Influence Model in Liberty Times doesn¡¦t have significant level. Meanwhile, Liberty Times and Taiwan Shin Wen News' prediction of media usage in horizontal communication don¡¦t have significant level. At last, there are only Liberty Times and Public Daily News's media usage prediction have significant level in informal communication. Keywords:intra-organization, media usage, face to face, telephone, e-mail, written document, formal communication, informal communication, upward communication, horizontal communication, downward communication, Media Richness, Social Influence Model.

This dissertation studies the design of an efficient adaptive digital baseband predistorter for modern cellular handsets that combines low power consumption, low implementation complexity, and high performance. The proposed enhancements are optimized for hardware implementation. We first present a thorough study of the optimal spacing of linearly-interpolated lookup table predistorters supported by theoretical calculations and extensive simulations. A constant-SNR compander that increases the predistorter's supported input dynamic range is derived. A corresponding low-complexity approximation that lends itself to efficient hardware design is also implemented in VHDL and synthesized with the Synopsys Design Compiler. This dissertation also proposes an LMS-based predistorter adaptation that is optimized for hardware implementation and compares the effectiveness of the direct and indirect learning architectures. A novel predistorter design with quadrature imbalance correction capability is developed and a corresponding adaptation scheme is proposed. This robust predistorter configuration is designed by combining linearization and I/Q imbalance correction into a single function with the same computational complexity as the widespread complex-gain predistorter.

Bakgrund: Telefonrådgivning på vårdcentral utgör en stor del av distriktssköterskors arbete. När distriktssköterskor saknar visuell kontakt med vårdsökare i telefonen ställs andra krav på kommunikationen mellan distriktssköterskor och vårdsökande. I takt med den ökade invandringen i Sverige träffar distriktssköterskor på utlandsfödda vårdsökande med språkförbistring i allt större utsträckning. Det behövs därför mer forskning inom detta område. Syfte: Syftet med denna studie är att beskriva distriktssköterskors erfarenheter av telefonrådgivning på vårdcentral till vårdsökande som inte har svenska som modersmål. Metod: Designen på studien är en kvalitativ deskriptiv intervjustudie med induktiv ansats. Datamaterialet utgjordes av tio intervjuer med distriktssköterskor på vårdcentral. Analys gjordes med hjälp av kvalitativ innehållsanalys. Resultat: Ur analysen framträder fyra kategorier Att främja samspel i kommunikationen, Att träffa på svårigheter/ hinder i samtalet, Att använda organisatoriska strategier, Att använda sin kompetens. Slutsats: Att nå överensstämmelse i kommunikationen ansågs som något av det viktigaste i arbetet med telefonrådgivning.  Kulturella skillnader och språkförbistring gjorde telefonrådgivningen utmanande. Andrahandsinformation gjorde det svårt att veta att korrekt information gavs samt att sekretessen upprätthölls. Distriktssköterskorna beskrev oro för felbedömning vid samtal med uppringare med språkförbistring. Att förmedla trygghet ansågs viktigt vid telefonrådgivning till utlandsfödda vårdsökare. Distriktssköterskorna i studien eftersökte organisatoriskt stöd och utbildning för att lättare kunna arbeta med telefonrådgivning. / Background: Telephone advice and triage at health care centers constitutes a big part of the daily tasks a district nurse perform. As the tele nurses lacks visual contact with their patients, there are greater demands in the communication as opposed to face-to-face encounters. As the immigration increases in Sweden, the district nurse encounters an increasing amount of foreign born callers with language barriers. Therefore, more research in this area is necessary. Aim: The aim of this study is to describe distric nurses experiences of telephone nursing to healthcare seekers with other native language than Swedish. Method: The study design is a qualitative descriptive interview study with an inductive approach. Data was collected through ten individual interviews with district nurses in health center and the data was analyzed by content analysis. Results: Four categories emerged from the analysis: To encourage synergetic communication, To encounter obstacles in the conversation, To practice organizational strategies, To utilize one's competence. Conclusion: To pursue mutuality in communication and to conclude a common decision was seen among the most important aspects of the telephone nursing advisory. Cultural differences and language barriers caused the telephone nursing to become a challenging task for the nurses. Secondary information received through friends and relatives introduced an uncertainty to determine information correctness and whether the secrecy remained upheld. The district nurses expressed concern of misjudgment during conversations with callers who showed language inabilities. To bring security was noted as crucial in telephone nursing for foreign born callers. Furthermore, the district nurse needs to be confident in oneself. The district nurses in this study sought for organizational support and education.