This dissertation is focused on multi-service and direct sequence code division multiple access (DS/CDMA) wireless cellular systems. The reverse link performance of a slotted DS/CDMA cellular system with multi-service traffic is analyzed. Services with/without packet retransmission to meet their Quality of Service, share the entire bandwidth. Packet failure probabilities and packet delay are obtained based on analyzing the mutual interaction among services. The impacts of power level allocation and power control error of services on capacity, throughput and delay are analyzed under given Quality of Service. The system capacity is maximized by appropriate power allocation. The impact of power control error on capacity is dependent on whether packet retransmission is allowed or not. Admission control policies for multi-service systems are proposed and analyzed. Both nonprioritized and prioritized admission control are studied. Services difference in terms of resource requirement and degree of importance are considered. Analytical models are developed. Blocking probability of each type of calls are found under given amount of traffic. Fair access by soft capacity is addressed. The cost of protecting certain type(s) of calls on the rest of calls is investigated. The impact of traffic distribution on the performance of the policies is also examined. In a hierarchical cellular system, user mobility estimation helps channel assignment so as to reduce the handoff rate and avoid high mobility users travel among small cells. Two different strategies are compared. It is found that when high mobility users are served by overlay macrocells, call drop rate is reduced. Speed estimation error only has limited impact on the system performance. User membership in a cellular CDMA network is simulated based on the estimation of the local mean value of the pilot signal from surrounding base stations. The base station providing strongest pilot local mean controls the mobile station. Simulation is conducted under different fading environments. Two performance measurements are simulated: the number of membership switchings per second and the probability of wrong base station selection. An optimum window length for filtering out Rayleigh fading is found. Simulation results are in good fit with those of analysis. / Graduate

Le droit de retour légal est celui en vertu duquel une personne succède à des biens qui avaient été remis gratuitement au défunt décédé sans postérité. Il s’agit d’une institution ancienne dont le fondement premier était traditionnellement la conservation des biens dans la famille. Apparu en droit romain, appliqué dans l’ancien droit français, le retour légal fut inséré in extremis dans le Code Napoléon, à côté du droit de retour de nature conventionnelle qu’il est loisible aux parties de stipuler. Des trois cas de retour prévus en 1804, deux furent supprimés par la loi du 3 janvier 1972. Il fallut attendre la loi du 3 décembre 2001 pour qu’à l’article 757-3 un nouveau droit de retour légal soit instauré au bénéfice des frères et soeurs qui, du fait de la réforme, se trouvaient primés par le conjoint dans la dévolution ab intestat. Puis la loi du 23 juin 2006 instaura à son tour à l’article 738-2 un droit de retour légal au profit des père et mère qui venaient de perdre leur qualité d’héritier réservataire. Dans ces deux cas, on observe que l’instauration du droit de retour légal constitue une contrepartie, pour les uns de leur exclusion de la dévolution par le conjoint, pour les autres de la perte du bénéfice de la réserve : fonction originale pour un droit de retour légal. Si les fondements des textes nouveaux ne sont pas évidents à mettre en lumière, leurs régimes novateurs soulèvent également de nombreuses difficultés d’applications et d’interprétations. Naguère, le retour légal organisait la dévolution successorale d’un bien en fonction de son origine dont il résultait une dualité de succession. Aujourd’hui, le retour légal n’organise plus que la dévolution successorale d’une portion de bien en tenant compte de son origine et l’on doute qu’il constitue dans tous les cas une succession anomale impliquant une dualité de succession. Ces incertitudes engagent à se demander s’il est possible de déroger au retour légal et comment. Au-delà de la dérogation conventionnelle, la modification et même l’abrogation des textes doivent être envisagées. / The statutory reversion right is the right under which a person inherits assets which were returned free of charge to the deceased who died leaving no descendants. It is an old institution which primary basis is, traditionally, the preservation of assets in the family. Established in Roman law, applied in old French law, statutory reversion was inserted in extremis in the Napoleonic code (the French civil code) next to the conventional reversion right which can be stipulated by the two parties within the framework of a transfer contract inter vivos. Out of the three cases provided in 1804, two were removed by the law of January 3, 1972. But it was not until December 3, 2001 that was established, in article 757-3 of the Civil Code, a new statutory reversion right in favour of the brothers and sisters, who, as a consequence of the reform, were superseded by the spouse in the transfer under intestate succession. Then the law of June 23, 2006 established, in turn, in article 738-2 of the Civil Code, a statutory reversion right in favour of the father and mother who had just lost their qualification of rightful heirs. In both cases, we can notice that the establishment of the statutory reversion right constitutes a counterpart, on one hand according to the exclusion for transfer by the spouse, on the other hand, the loss of the benefit of reservation: a particular role for the statutory reversion right. If the bases of the new texts are not easily highlighted, their innovative schemes also raise numerous difficulties of application and interpretation. Formerly, statutory reversion established transmission of property by inheritance according to its origin from which a duality in terms of inheritance resulted. Nowadays, statutory reversion only establishes transmission of property by inheritance of a portion of goods, taking into account its origin, and this raises some doubt as to whether it shall constitute, in all cases, an anomalous succession implying duality in terms of inheritance. This results in uncertainties which lead to wonder if it is possible to derogate from the statutory reversion and how this could be done. Beyond variation by agreement, the modification and even the repeal of texts must be considered.

Powerful remote sensing techniques can covert time variability of polarization profiles of stellar spectral lines into vector magnetic fields maps of stellar surfaces. These techniques are widely applied to interpret observations but have been tested using only simplistic tests. It would be of interest to test magnetic inversion methods using polarization spectra simulated for realistic and physical models of stellar magnetic fields provided by recent 3D numerical simulations. Doppler Imaging is a method to reconstruct vector magnetic field maps of stellar surfaces from variation of polarization profiles. The work in this thesis presents numerical experiments to evaluate the performance of Magnetic Doppler Imaging (MDI) code INVERS10. The numerical experiments showed that in given high-resolution observations in four Stokes parameters, the code is capable of reconstructing magnetic field vector distributions, over the stellar surface, simultaneously and without any prior assumptions about the magnetic field geometry. Input data consists of polarization measurements in the line profiles and the reconstruction is performed by solving the regularized inverse problem. Right results were obtained by testing different type of models covering simple, complex and unusual complex magnetic field distribution. Whilst using incomplete Stokes parameter datasets containing only Stokes I and V profiles, the INVERS10 code was able to reconstruct a global stellar magnetic fields of only simple models and give accurate and reliable results. Testing the code with different inclination and azimuth angle successfully gave the lowest deviation when same values are used from the true map.

Programs are not only a tool for the simplification or automation of everyday tasks; they also represent a significant time and money investment. A program's life may span years, or even decades, which creates certain risks for the stakeholders involved. To mitigate the risks associated with these legacy systems, software renovation can be undertaken. Software renovation can be described as a series of processes and/or tools used to modernize a legacy system, thereby preserving and maintaining the investment it represents while decreasing the risks associated with it. In this thesis, the focus is on renovation of software created by in-house development. A series of case studies will be examined to demonstrate basic renovation strategies, including the formation of goals for a renovation and exploring trade-offs between robustness, performance, and usability.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg in fulfillment of the requirements for the degree of Master of Science. May 2017 / Plagiarism is a serious problem in academia. It is prevalent in the computing discipline where students are expected to submit source code assignments as part of their assessment; hence, there is every likelihood of copying. Ideally, students can collaborate with each other to perform a programming task, but it is expected that each student submit his/her own solution for the programming task. More so, one might conclude that the interaction would make them learn programming. Unfortunately, that may not always be the case. In undergraduate courses, especially in the computer sciences, if a given class is large, it would be unfeasible for an instructor to manually check each and every assignment for probable plagiarism. Even if the class size were smaller, it is still impractical to inspect every assignment for likely plagiarism because some potentially plagiarised content could still be missed by humans. Therefore, automatically checking the source code programs for likely plagiarism is essential. There have been many proposed methods that attempt to detect source code plagiarism in undergraduate source code assignments but, an ideal system should be able to differentiate actual cases of plagiarism from coincidental similarities that usually occur in source code plagiarism. Some of the existing source code plagiarism detection systems are either not scalable, or performed better when programs are modified with a number of insertions and deletions to obfuscate plagiarism. To address this issue, a graph-based model which considers structural similarities of programs is introduced to address cases of plagiarism in programming assignments. This research study proposes an approach to measuring cases of similarities in programming assignments using an existing plagiarism detection system to find similarities in programs, and a graph-based model to annotate the programs. We describe experiments with data sets of undergraduate Java programs to inspect the programs for plagiarism and evaluate the graph-model with good precision. An evaluation of the graph-based model reveals a high rate of plagiarism in the programs and resilience to many obfuscation techniques, while false detection (coincident similarity) rarely occurred. If this detection method is adopted into use, it will aid an instructor to carry out the detection process conscientiously. / MT 2017

University of Macau / Faculty of Arts and Humanities. / Department of English

University of Macau / Faculty of Arts and Humanities. / Department of English

by Kwok Ming Shan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 102-[109]). / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Cellular Radio Systems --- p.3 / Chapter 1.2 --- Code Division Multiple Access (CDMA) --- p.7 / Chapter 1.2.1 --- Direct Sequence CDMA (DS-CDMA) --- p.8 / Chapter 1.2.2 --- Frequency Hopping CDMA (FH-GDMA) --- p.11 / Chapter 1.2.3 --- Time Hopping CDMA (TH-CDMA) --- p.12 / Chapter 1.3 --- Propagation Characteristics --- p.12 / Chapter 1.3.1 --- Signal Strength Prediction - Path Loss --- p.13 / Chapter 1.3.2 --- Signal Variability --- p.17 / Chapter 1.3.3 --- Delay Spread --- p.23 / Chapter 1.3.4 --- Coherence Bandwidth --- p.23 / Chapter 1.4 --- Power Control in Cellular Radio Systems --- p.24 / Chapter 1.4.1 --- Centralized Power Control --- p.24 / Chapter 1.4.2 --- Distributed Power Control --- p.25 / Chapter 1.4.3 --- CDMA Power Control --- p.29 / Chapter 2 --- Contributions --- p.39 / Chapter 3 --- ACI Analysis of the Reverse-Link --- p.41 / Chapter 3.1 --- Adjacent Cell Interference --- p.42 / Chapter 3.2 --- Adjacent Cell Interference Analysis --- p.43 / Chapter 3.2.1 --- Interference Analysis of Hexagonal Cells --- p.43 / Chapter 3.2.2 --- Interference Analysis of Circular Cell Structure --- p.47 / Chapter 3.3 --- Closed-form of Adjacent Cell Interference --- p.51 / Chapter 3.4 --- Generalization to Irregular Cell Structure --- p.54 / Chapter 3.5 --- Conclusions --- p.57 / Chapter 4 --- ACI Analysis of Reverse-Link with Log-normal Shadowing --- p.59 / Chapter 4.1 --- Interference with Shadowing --- p.59 / Chapter 4.2 --- Conclusions --- p.66 / Chapter 5 --- ACI Analysis of Microcell --- p.68 / Chapter 5.1 --- Propagation Characteristics of Microcellular Radio Systems --- p.69 / Chapter 5.2 --- CDMA Microcellular Radio Systems --- p.70 / Chapter 5.3 --- Results and Discussions --- p.74 / Chapter 5.4 --- Conclusions --- p.76 / Chapter 6 --- Outage Probability Analysis of Imperfect Power Control --- p.77 / Chapter 6.1 --- Fast Fading of Signal --- p.78 / Chapter 6.2 --- Imperfect Power Control in CDMA --- p.81 / Chapter 6.3 --- Conclusions --- p.85 / Chapter 7 --- Conclusions --- p.88 / Chapter 8 --- Examples of CDMA Cellular Radio Systems --- p.91 / Chapter 8.1 --- Qualcomm CDMA system --- p.91 / Chapter 8.1.1 --- Forward-link --- p.92 / Chapter 8.1.2 --- Reverse-link --- p.93 / Chapter 8.1.3 --- Reverse-Link Open-Loop Power Control --- p.94 / Chapter 8.1.4 --- Reverse-Link Closed-Loop Power Control --- p.95 / Chapter 8.1.5 --- Forward-Link Power Control --- p.96 / Chapter 8.2 --- Interdigital Broadband CDMA System --- p.96 / Appendix --- p.97 / Chapter A --- Derivation of the PDF of the fast fading signal power --- p.97 / Chapter B --- Derivation of the Mean-to-standard deviation ratio --- p.98 / Chapter C --- Acronyms --- p.100 / Bibliography --- p.102

by Tsan-Fai Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 64-68). / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Review on spread spectrum communications --- p.1 / Chapter 1.2 --- The spread spectrum techniques --- p.2 / Chapter 1.2.1 --- Direct Sequence (DS) Systems --- p.2 / Chapter 1.2.2 --- Frequency Hopping (FH) Systems --- p.2 / Chapter 1.2.3 --- Time Hopping (TH) Systems --- p.4 / Chapter 1.2.4 --- Hybrid Systems --- p.4 / Chapter 1.3 --- Existing Applications of the spread spectrum systems --- p.5 / Chapter 1.4 --- Organization of the thesis --- p.6 / Chapter 2 --- The Concept of Duality --- p.7 / Chapter 2.1 --- Multi-Carrier Systems - An Overview --- p.7 / Chapter 2.2 --- Orthogonal Frequency Division Multiplexing --- p.8 / Chapter 2.2.1 --- Bandwidth Efficiency --- p.9 / Chapter 2.2.2 --- Spectral Efficiency --- p.10 / Chapter 2.2.3 --- Effects of fading --- p.11 / Chapter 2.3 --- Applications of OFDM in multiple access --- p.13 / Chapter 2.3.1 --- ST-CDMA --- p.13 / Chapter 2.3.2 --- MC-DS-CDMA --- p.14 / Chapter 2.3.3 --- OFDM-CDMA --- p.15 / Chapter 2.4 --- Duality - Time-Frequency Interrelation --- p.16 / Chapter 3 --- Performance of Multi-Carrier CDMA System --- p.17 / Chapter 3.1 --- System Model --- p.17 / Chapter 3.2 --- Performance Analysis --- p.20 / Chapter 3.2.1 --- Gaussian Channel --- p.20 / Chapter 3.2.2 --- Fading Channel --- p.24 / Chapter 3.3 --- Performance with Pulse Shape --- p.33 / Chapter 3.4 --- Appendix --- p.34 / Chapter 4 --- Signal Design Criteria for MC-CDMA System --- p.36 / Chapter 4.1 --- Existence of Signal Distortion --- p.37 / Chapter 4.2 --- Measures of the Signal Envelope Fluctuation --- p.38 / Chapter 4.3 --- Complementary Sequences --- p.41 / Chapter 4.4 --- Crest Factors --- p.42 / Chapter 4.4.1 --- Time-limited Pulse --- p.43 / Chapter 4.4.2 --- Ideally Band-Limited Pulses --- p.43 / Chapter 4.4.3 --- Shaped Pulses --- p.45 / Chapter 4.5 --- Spectrally Efficient Complementary (SEC) Sequences --- p.48 / Chapter 4.6 --- Construction of Spectrally Efficient Complementary(SEC) Sequences --- p.50 / Chapter 4.7 --- Generalized Multiphase Spectrally Efficient Complementary Sequences --- p.55 / Chapter 5 --- Summary and Future Extensions --- p.58 / Chapter 5.1 --- Summary of the Results --- p.58 / Chapter 5.2 --- Topics for Future Research --- p.59 / Appendix / Chapter A --- Exhaustive search of MPSEC sequences --- p.61 / Chapter B --- Papers derived from this thesis --- p.63 / Bibliography --- p.64

by Yin-Man Lee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 82-[87]). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview of MC-CDMA --- p.1 / Chapter 1.2 --- System Model --- p.3 / Chapter 1.3 --- Receiver Optimization --- p.7 / Chapter 1.4 --- Transmitter Optimization --- p.9 / Chapter 1.5 --- Nonlinearly Constrained Optimization --- p.10 / Chapter 1.6 --- Outline of Thesis --- p.11 / Chapter 2 --- Centralized Transmitter Optimization for MC-CDMA Systems --- p.13 / Chapter 2.1 --- Introduction --- p.13 / Chapter 2.2 --- Problem Development --- p.15 / Chapter 2.3 --- Lagrangian Optimization Approaches --- p.16 / Chapter 2.3.1 --- Penalty Function Method --- p.17 / Chapter 2.3.2 --- Barrier Function Method --- p.19 / Chapter 2.3.3 --- Powell's Method and Augmented Lagrangian Method --- p.21 / Chapter 2.4 --- Optimal FDMA System --- p.23 / Chapter 2.5 --- Modified Centralized Optimization Schemes --- p.25 / Chapter 2.6 --- Performance --- p.27 / Chapter 2.6.1 --- Typical Behavior --- p.27 / Chapter 2.6.2 --- Average Performance --- p.32 / Chapter 2.7 --- Summary --- p.38 / Chapter 3 --- Decentralized Transmitter Optimization for MC-CDMA Sys- tems --- p.39 / Chapter 3.1 --- Introduction --- p.39 / Chapter 3.2 --- System Model --- p.41 / Chapter 3.3 --- Optimization --- p.42 / Chapter 3.3.1 --- Receiver Optimization --- p.43 / Chapter 3.3.2 --- Single-user Transmitter Optimization --- p.44 / Chapter 3.3.3 --- Decentralized Transmission Scheme --- p.45 / Chapter 3.3.4 --- Multirate Transmission with Decentralized Transmission Scheme --- p.47 / Chapter 3.4 --- Performance --- p.48 / Chapter 3.5 --- Summary --- p.57 / Chapter 4 --- Performance Evaluation of Various Adaptive Transmission Schemes --- p.59 / Chapter 4.1 --- Introduction --- p.59 / Chapter 4.2 --- Comparison of Different Adaptive Transmission Schemes --- p.61 / Chapter 4.3 --- Adaptive Transmission Schemes with K > M --- p.64 / Chapter 4.4 --- Modified Adaptive Transmission Scheme with Graceful Degrada- tion in the SNR --- p.68 / Chapter 4.5 --- Summary --- p.71 / Chapter 5 --- Conclusions and Future Work --- p.73 / Chapter 5.1 --- Conclusions --- p.73 / Chapter 5.2 --- Future Work --- p.75 / A The Hungarian Method for Optimal Frequency Assignment --- p.76 / Bibliography --- p.82