Dissertations / Theses on the topic 'THRESHOLD SENSITIVE'

I tested the twin-threshold model, a risk-sensitive foraging model incorporating both a starvation threshold and a higher reproductive threshold. The model predicts risk-adverse foraging when an animal's energy state is close to the starvation threshold and risk-prone foraging when the animal's energy state is close to the reproductive threshold. Wild rufous hummingbirds (Selasphorus rufus) were presented with a choice of three artificial flower types that had either no, moderate or high variability around a common mean. I manipulated energy state by changing either the mean nectar volume or altering the cost of foraging (long versus short corollas). When the energy state of hummingbirds was close to the reproductive threshold they preferred the variable options. When the energy state of hummingbirds was close to the starvation threshold they preferred the nil option. Hummingbirds responded in a manner consistent with the twin-threshold model.
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Timeliness in delivering packets for delay-sensitive applications is an important QoS (Quality of Service) measure in many systems, notably those that need to provide real-time performance. In such systems, if delay-sensitive traffic is delivered to the destination beyond the deadline, then the packets will be rendered useless and dropped after received at the destination. Bandwidth that is already scarce and shared between network nodes is wasted in relaying these expired packets. This thesis proposes that a deterministic per-hop delay can be achieved by using a dynamic queue threshold concept to bound delay of each node. A deterministic per-hop delay is a key component in guaranteeing a deterministic end-to-end delay. The research aims to develop a generic approach that can constrain network delay of delay-sensitive traffic in a dynamic network. Two adaptive queue management schemes, namely, DTH (Dynamic THreshold) and ADTH (Adaptive DTH) are proposed to realize the claim. Both DTH and ADTH use the dynamic threshold concept to constrain queuing delay so that bounded average queuing delay can be achieved for the former and bounded maximum nodal delay can be achieved for the latter. DTH is an analytical approach, which uses queuing theory with superposition of N MMBP-2 (Markov Modulated Bernoulli Process) arrival processes to obtain a mapping relationship between average queuing delay and an appropriate queuing threshold, for queue management. While ADTH is an measurement-based algorithmic approach that can respond to the time-varying link quality and network dynamics in wireless ad hoc networks to constrain network delay. It manages a queue based on system performance measurements and feedback of error measured against a target delay requirement. Numerical analysis and Matlab simulation have been carried out for DTH for the purposes of validation and performance analysis. While ADTH has been evaluated in NS-2 simulation and implemented in a multi-hop wireless ad hoc network testbed for performance analysis. Results show that DTH and ADTH can constrain network delay based on the specified delay requirements, with higher packet loss as a trade-off.

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FACEPE
análise da similaridade entre algoritmos de aprendizagem de máquina é um importante aspecto na área de Meta-Aprendizado, onde informações obtidas a partir de processos de aprendizagem conhecidos podem ser utilizadas para guiar a seleção de algoritmos para tratar novos problemas apresentados. Essa similaridade é geralmente calculada através de métricas globais de desempenho, que omitem informações importantes para o melhor entendimento do comportamento dos algoritmos. Também existem abordagens onde é verificado o desempenho individualmente em cada instância do problema. Ambas as abordagens não consideram os custos associados a cada classe do problema, negligenciando informações que podem ser muito importantes em vários contextos de aprendizado. Nesse trabalho são apresentadas métricas para a avaliação do desempenho de algoritmos em cenários sensíveis a custo. Cada cenário é descrito a partir de um método para escolha de limiar para a construção de um classificador a partir de um modelo aprendido. Baseado nos valores de desempenho em cada instância, é proposta uma forma de avaliar a similaridade entre os algoritmos tanto em nível de problema como em nível global. Os experimentos realizados para ilustrar as métricas apresentadas neste trabalho foram realizados em um estudo de Meta-Aprendizado utilizando 19 algoritmos para a classificação das instâncias de 152 problemas. As medidas de similaridades foram utilizadas para a criação de agrupamentos hierárquicos. Os agrupamentos criados mostram como o comportamento entre os algoritmos diversifica de acordo com o cenário de custo a ser tratado.
The analysis of the similarity between machine learning algorithms is an important aspect of Meta-Learning, where knowledge gathered from known learning processes can be used to guide the selection of algorithms to tackle new learning problems presented. This similarity is usually calculated through global performance metrics that omit important information about the algorithm behavior. There are also approaches where the performance is verified individually on each instance of a problem. Both these approaches do not consider the costs associated with each problem class, hence they neglect information that can be very important in different learning contexts. In this study, metrics are presented to evaluate the performance of algorithms in cost sensitive scenarios. Each scenario is described by a threshold choice method, used to build a crisp classifier from a learned model. Based on the performance values for each problem instance, it is proposed a method to measure the similarity between the algorithms in a local level (for each problem) and in a global level (across all problems observed). The experiments used to illustrate the metrics presented in this paper were performed in a Meta-Learning study using 19 algorithms for the classification of the instances of 152 learning problems. The similarity measures were used to create hierarchical clusters. The clusters created show how the behavior of the algorithms diversifies according to the cost scenario to be treated.

A dismenorreia primária ou menstruação dolorosa na ausência de patologia pélvica é uma condição comum e muitas vezes debilitante considerada uma das queixas mais frequentes no dia-a-dia da clínica ginecológica, afetando entre 45 e 95% das mulheres que menstruam. Não há consenso na literatura sobre os limiares experimentais dessas mulheres. Na dor pélvica crônica, a diminuição dos limiares sensitivo e doloroso estão associados aos quadros de sensibilização central e hiperalgesia, necessitando de tratamento focado nesse quadro sindrômico. Se os limiares dolorosos das mulheres com dismenorreia seguirem um padrão compatível como o encontrado em mulheres com dor pélvica crônica, poderemos melhorar o tratamento dessas pacientes, abordando também as alterações neuroplásticas e do humor. Objetivo primário: Avaliar os limiares experimentais de voluntárias portadoras de dismenorreia primária moderada ou grave. Métodos e Procedimentos: Na entrevista, as participantes foram submetidas a uma avaliação psicométrica com as escalas EVA (escala visual analógica de dor), Questionário de McGill (analisa várias dimensões da dor), Escala de Ansiedade e Depressão para Hospital Geral (HAD), avaliação sócio-demográfica, antropométrica e ainda um questionário relacionado ao ciclo menstrual em geral, abordando ainda questões relacionadas a história familiar, absenteísmo no trabalho ou escola, uso e eficiência medicamentosa, prática e frequência de atividade física, entre outras. Em seguida, foram analisados os limiares sensitivo e doloroso através do aparelho de eletroestimulação nervosa transcutânea TENS e o limiar doloroso por meio de pressão transcutânea, algômetro. Resultados: Participaram do estudo 48 voluntárias divididas em dois grupos: Grupo Estudo, composto por 24 mulheres (com dismenorreia primária moderada ou grave) e o Grupo Controle composto por 24 mulheres (sem dismenorreia ou com dismenorreia primária leve). A mediana do limiar doloroso obtido através da estimulação nervosa transcutânea foi de 10,11mA no grupo de estudo e 11,92mA no grupo controle e na algometria de 1,86kg/cm² e 2,28kg/cm² respectivamente. Entre as mulheres com dismenorreia primária moderada ou grave 70 % relataram que a mãe ou irmã já sofreram ou sofrem de cólicas menstruais, 70 % não praticam nenhum tipo de atividade física, 58,3%possui algum grau de ansiedade pelo HAD e 12,5% de depressão pelo HAD, 87,5% fazem uso de medicação para dor durante o período menstrual e 33,3% faltaram de suas atividades nos últimos três meses devido a dismenorreia.
Primary dysmenorrhea or painful menstruation in the absence of pelvic pathology is a common condition and often debilitating considered one of the most frequent complaints in day-to-day gynecologic practice, affecting between 45 and 95% of menstruating women. There is no consensus in the literature on the experimental thresholds of these women In chronic pelvic pain, decreased sensory and pain thresholds are associated with the frames of central sensitization and hyperalgesia, requiring treatment focused on this syndromic. If the painful threshold of women with dysmenorrhea follow a pattern consistent as found in women with chronic pelvic pain, we can improve the treatment of these patients also addressing the neuroplastic and mood changes. Specific Objective: Evaluate voluntary experimental thresholds with moderate or severe primary dysmenorrhea. Methods and Procedures: In the interview, participants were subjected to psychometric assessment to the VAS scales (visual analog pain scale), McGill Questionnaire (analyzes various dimensions of pain), Anxiety Scale and Depression for General Hospital (HAD), socio-demographic, antropometric assessment and also a questionnaire related to the menstrual cycle in general, adressing issues related to family history, absenteeism at work or school, use and drug efficiency, practice and frequency of physical activity, among others. Then the sensitive and painful thresholds were analyzed through transcutaneous electrical nerve stimulation TENS device and the pain threshold through transcutaneous pressure algometer. Results: The study included 48 volunteers divided into two groups: Study Group, composed of 24 women (with moderate or severe primary dysmenorrhea), the control group composed of 24 women (no or mild dysmenorrhea primary dysmenorrhea). The median pain threshold obtained by transcutaneous nerve stimulation was 10,11mA corresponding to the study group and the control group 11,92mA and algometry of 1,86kg / cm² and 2,28kg / cm² respectively. Among women with moderate or severe primary dysmenorrhea 70 % reported that the mother or sister have suffered or are suffering from menstrual cramps, 70 % do not practice any physical activity, 58.3 % have some degree of anxiety by the HAD and 12.5 % of depression by the HAD, 87.5 % make use of medication for pain during the menstrual period and 33.3 % missed their activities in the last three months because of dysmenorrheal.

Substantial evidences show that tinnitus is associated with hearing loss. However, approximately 10% of tinnitus patients attending an ENT/Audiology clinic for their problems have hearing within normal audiometric thresholds. The general consensus on the roles of hearing loss in triggering tinnitus seems not applicable in this minority group. The absence of any grossly abnormal audiometric findings to explain their tinnitus leaves the clinician with a diagnostic dilemma and presents difficulties in dealing with the patients. The aim of this study was therefore to scrutinize auditory functioning in a sample of tinnitus subjects with normal hearing thresholds and non-tinnitus normally hearing control participants. Five tests were applied: Audioscan, Transient Evoked Otoacoustic Emission (TEOAE), Distortion Product Otoacoustic Emission (DPOAE), Threshold Equalising Noise (TEN) test and Contralateral Suppression of TEOAE (CSTEOAE). Optimal parameters for these tests have been defined and subsequently used to detect subtle auditory deficit in tinnitus patients with normal hearing thresholds. Twenty-seven tinnitus patients with hearing thresholds within normal limit participated in this study. A total of 27 non-tinnitus volunteers with similar thresholds were recruited as controls. Significant more Audioscan notches were found in tinnitus patients than in controls, particularly at 3001 to 8000 Hz region. Moreover, abnormal TEOAE was significantly more in tinnitus patients than in controls. No significant difference was observed in DPOAE, TEN and CSTEOAE test. Only one patient was found with abnormal TEN test and no TEOAE suppression, which led to the discovery of a large vestibular schwannoma. VI In summary, these results confirm the possible existence of subtle auditory deficit in tinnitus patients with normal hearing thresholds. However, combination of cochlear and retrocochlear abnormality may also possible. The presence of tinnitus without concomitant hearing loss in this group suggests that it may be an early sign of diseases that are only diagnosed after the onset of hearing loss.

Neuralgia pós-herpética trigeminal (NPH), neuralgia idiopática do trigêmeo (NIT) e síndrome da ardência bucal (SAB) são doenças neuropáticas da face, caracterizadas por dor na ausência de sinais que evidenciem a causas. Este estudo teve por objetivos determinar as características sensitivas, olfativas, gustativas e salivares em doentes com NPH, NIT e SAB comparados a controles. Foram avaliados 20 doentes de cada grupo, diagnosticados de acordo com critérios da International Association for the Study of Pain (IASP), e 60 indivíduos saudáveis, através de um protocolo sistematizado que incluiu os seguintes testes quantitativos sensitivos: limiares térmicos (frio e calor), limiares mecânicos tácteis, limiares dolorosos de superfície, limiares gustativos (doce, azedo, salgado e amargo), limiares olfativos e fluxo salivar. Os testes foram realizados no território de inervação trigeminal. Os dados foram analisados através dos testes estatísticos ANOVA 1 fator, Tukey, Kruskal-Wallis e Dunn, e o nível de significância foi de 5%. Os limiares térmicos de frio foram diferentes (maiores) somente no ramo mandibular dos doentes com NPH (p=0,001) e os limiares térmicos de calor foram diferentes (maiores) em todos os ramos trigeminais nos doentes com NPH e SAB (p=0,001); a sensibilidade mecânica táctil estava alterada no ramo mandibular de doentes com NPH (p=0,001) e em todos os ramos trigeminais dos doentes com SAB (p= 0,001; p=0,004 e p=0,001); os limiares gustativos salgado e doce, além do limiar olfativo, foram maiores em todos os doentes quando comparados aos controles (p=0,004; p=0,001 e p=0,0389); o sabor ácido obteve os menores limiares e não foram encontradas diferenças para a identificação do sabor amargo ou na avaliação salivar quantitativa (p=0,1694 e p=0,001). Este estudo apresentou evidências de anormalidades sensitivas nos doentes com dor neuropática trigeminal, tanto somestésicas como gustativas e olfativas. A sensibilidade somatosensitiva apresentou-se mais alterada nos doentes com NPH e SAB quando comparados a NIT e aos controles. Mecanismos periféricos e centrais relacionados à percepção e modulação sensitiva podem estar envolvidos na fisiopatologia dos achados aqui observados
Trigeminal postherpetic neuralgia (PHN), idiopathic trigeminal neuralgia (ITN) and burning mouth syndrome (BMS) are painful neuropathies with no clear signs about their causes. The objectives of this study were to determine somatosensory, olfactory, gustative and salivary characteristics of patients with PHN, ITN and BMS compared to controls. Twenty patients from each group, diagnosed according to the criteria from the International Association for the Study of Pain (IASP), and 60 healthy controls were evaluated with a systematized quantitative approach which included thermal (cold and warm), mechanical (tactile), pain, gustative (sweet, sour, salty and bitter) and olfactory thresholds, and quantitative salivary flow evaluation. Data were analyzed with ANOVA 1 factor, Tukey, Kruskal-Wallis and Dunn tests with a level of significance of 5%. Thermal thresholds for cold were different (higher) only in the mandibular branch of patients with PHN (p=0.001) and warm thresholds were higher in all trigeminal branches of PHN and BMS (p=0,001); tactile mechanical sensitivity was altered at the mandibular branch of PHN (p=0,001) and in all trigeminal branches of BMS (p= 0,001; p=0,004 e p=0,001). The salty, sweet and olfactory thresholds were higher in all studied groups (p=0,004; p=0,001 e p=0,0389); the sour threshold was lower and there were no differences in bitter taste or salivary flow (p=0,1694 e p=0,001). This study showed evidences of somatosensory, gustative and olfactory abnormalities in patients with neuropathic orofacial pain. Somatosensory findings were discrete in ITN and more common in PHN and BMS. Peripheral and central mechanisms of perception and modulation could be involved in the physiopathology of these findings

A neuropatia diabética causa diminuição ou perda da sensibilidade protetora do pé, tornando-o mais vulnerável ao trauma mecânico e térmico. A profilaxia das complicações neuropáticas tem início pela identificação da perda de sensibilidade e, portanto, do comprometimento neurológico. O Pressure Specified Sensory Device(TM) (PSSD) é um equipamento desenvolvido para quantificar o limiar de pressão, aplicada sobre a pele, necessária para que o paciente perceba o estímulo provocado por: um ponto estático, um ponto em movimento, dois pontos estáticos e dois pontos em movimento. Denominamos grupo estudo, aos trinta e quatro pacientes diabéticos do tipo 2, sem história prévia de feridas e/ou amputações nos pés que foram submetidos à avaliação de sensibilidade cutânea utilizando-se o PSSD(TM). Foram realizados testes nos territórios cutâneos dos nervos fibular profundo, plantar medial e ramo calcâneo do nervo tibial posterior. Estímulos foram provocados segundo as modalidades: um ponto estático (1 PE), um ponto em movimento (1 PD), dois pontos estáticos (2 PE) e dois pontos em movimento (2 PD), para as duas últimas modalidades. Previamente às modalidades 2PE e 2PD determinou-se o limiar de discriminação entre dois pontos estáticos (D2PE) e em movimento (D2PD). Foram realizados apenas no grupo estudo, testes com o monofilamento de Semmes-Weisntein nº 5,07 (MSW) e com o diapasão de 128 Hz. Vinte e oito pacientes não-diabéticos, submetidos aos mesmos testes, formaram o grupo controle. Para os limiares de sensibilidade, encontramos valores superiores no grupo estudo (p < 0,05). Ao compararmos os limiares de sensibilidade alcançados pelos pacientes diabéticos sensíveis e não sensíveis ao estímulo promovido pelo MSW nº 5,07 verificamos que o p-valor variou entre 0,018 < p < 0,113 para 1 PE e 0,002 < p < 0,083 para 2 PE, conforme o território cutâneo estudado. Na comparação dos limiares de sensibilidade da modalidade 1 PD entre diabéticos sensíveis e insensíveis à vibração do diapasão de 128 Hz, as diferenças não foram estatisticamente significantes (p = 0,183). Os resultados obtidos nos permitiram sugerir que o dispositivo PSSD(TM) seja utilizado como forma de acompanhamento do comprometimento da fibra nervosa.
Neuropathy is a severe progressive loss of protective sensation on the feet, making the patient more vulnerable to mechanical trauma and consequently more suitable to the development of chronic wounds, major distortion of the foot bone architecture and eventually to limb amputation. Prophylaxis should be enforced to avoid foot ulceration and for that, evaluation of the degree of loss of sensation on the skin is essential. The PSSD (Pressure Specified Sensory Device(TM)) was developed in order to quantify the threshold of pressure applied to the skin that could be recognized as positive by the patient. Pressure of one or two points is tested both statically and with movement, thus assessing the function of fast and slow response nerve fibers. Threshold of two-point discrimination was also measured in mm. Thirty four (n = 34) diabetic patients, type II, with no previous history of wounds on the lower extremity were studied using the tests, one point static (1PE), one point moving (1PD) and two points static (2 PE), and moving (2 PD) on the cutaneous territory of the fibular nerve and posterior tibial nerve (two territories - medial plantar and calcaneous nerves). The control group (28 non diabetic patients) was assessed by the same exams and the results were compared. In the diabetic group the cutaneous territories were also evaluated using the conventional Semmes-Weinstein filament nº 5,07 e vibrometer of the 128 Hz. Altered values were observed for the static and dynamic tests over the three studied nerve territories. The differences were statically significant (p < 0,05). Comparing the threshold of sensibility between sensitive and non sensitive diabetic patients to MSW nº 5,07 test, we observed that p-value range was 0,018 0,113 when 1PE test was applied, and 0,002 0,083 when 2PE test was applied, according to the cutaneous territories evaluated. Numeric quantification of the threshold of pressure allows us to determine the status of the fiber/receptor structures as well as the functional deficit of nerve fibers. Our findings suggest that PSSD(TM) is an adjuvant tool to evaluate the degree of loss of sensation on the skin.

Wireless Sensor Network (WSN) is a kind of self-configuring network composed of a set of wireless sensor nodes (also called motes). The lifetime of WSN is limited because the sensor node works on battery life and it is hard to recharge the battery at regular basis because of the deployment of wireless sensor network in remote and hostile places. In order to prolong the network lifetime, a network routing protocol with high energy efficiency is necessary besides designing low-power sensor nodes. In Wireless sensor networks, several routing protocols have been developed to improve the various parameters such as stability period, throughput etc. Several Homogenous and heterogeneous Routing protocols were discovered in the domain of Wireless sensor networks. The homogenous network has all nodes of same energy and heterogeneous has nodes of different energies. But studies have shown that heterogeneous protocols are better to prolong the lifetime of the network. A clustering based homogenous protocol Low energy adaptive Clustering hierarchical (LEACH) gave a basic clustering approach to make efficient protocol for routing. After this many heterogeneous protocols were explored which successfully improved the throughput, lifetime etc of wireless sensor network. In this research the heterogeneous protocol, Distributed Energy efficient Clustering(DEEC),its enhanced Version EhancedDEEC(EDEEC) and their further improvements have been explored and have made them more efficient further by advanced distributed energy efficient clustering (DEEC) routing protocol for wireless sensor new node superadvanced node in addition to normal, advanced and super nodes as in EDEEC is taken to increase the stability period and longevity of the network. As energy cost is more in term of transmission of data than processing data in the nodes, so to optimize the transmission, reactive routing protocol TEEN is applied in this research. This saves a lot of energy and makes transmission better in terms of throughput, longevity of the network etc. This research has been simulated in matlab and successfully outperformed the LEACH, DEEC and EDEEC in terms of alive nodes, dead nodes and throughput.

Wireless sensor network (WSN) is an advancing technological field of wireless communication with a wide range of applications. It comprises of geographically wide-spread unattended micro-sensors. Such autonomous characteristics of nodes have led to design of various routing protocols which encounter performance augmentation with respect to energy efficiency and network lifetime. Design of routing protocols is highly contingent on the application which uses it. However, hierarchical cluster-based structure is ascertained to yield considerable potential. Rooted from it is the widely known cluster-based LEACH protocol. Considerable contribution is also done in protocols based upon genetic algorithms such as ERP and HCR. They tend to extend network lifetime but are liable to attainable modifications which can direct to better performances. The aim of this paper is to acquire effective fitness function to construct clusters efficiently which can operate with high stability and attain low energy dissipation over the rounds of transmission. Another moderation is the route configuration for aggregated data to be transmitted along the cluster heads only. Simulation and comparison with LEACH, TEEN and ERP shows that GA-TSRP is significantly stable for a number of transmission rounds. And thus, energy utilized is spread uniformly over an adequate duration of sensor network lifetime.

The Wireless Sensor Network consists of a large number of limited battery powered sensor nodes. These networks have wide range of applications related to areas like weather monitoring, forest monitoring, security and target monitoring, etc. The limited powered battery affects the network‟s lifetime. Various protocols have been developed to increase the network‟s lifetime. In this dissertation, we developed EECHR protocol, a clustering protocol for reactive network with threshold sensitive homogeneous sensor nodes. It includes an energy efficient cluster head selection and cluster formation techniques. It also includes an adaptive feature to make the BS aware of the status of nodes in the network which remains idle for long time. It also provides preference to the nodes sensing critical information to directly send their information to the BS. The nodes sensing critical information are released from the burden of becoming CH and they don‟t take part in CH selection. Our proposed protocol performs better than the other conventional protocol like LEACH, E-LEACH, I-LEACH. We also develop a multi hop routing protocol ATEEM for the homogeneous reactive network. It provides an energy efficient data transfer mechanism which is used by the critical nodes to transfer data to BS, by CHs to transmit data to BS and also by Non- CH node to transmit data to CH node. It includes an energy efficient cluster formation mechanism. We have also developed a mechanism to find the critical region in the given network area on the basis of information stored in the BS. It performed better than the EECHR protocol and TEEN protocol.

M.Sc.(Occupational Therapy), Faculty of Health Sciences, University of the Witwatersrand, 2009
Title: The agreement found between the sensory profiles of children 3-10 years and their parents Author: Elsje Geyser Promoter: Denise Franszen School: Therapeutic Sciences Faculty: Health Sciences Degree: MSc.OT Key Concepts: Sensory modulation dysfunction, sensory processing disorder, high threshold, low threshold, sensory profile, low registration behaviour, sensory seeking behaviour, sensory sensitive behaviour, sensation avoiding behaviour. In order to treat a child with sensory modulation disorder (SMD), the impact of SMD on the child’s occupational sphere should be taken into account. This includes the effect of SMD in the parent on the child’s development and behaviour. This study determined the probability of agreement between the parent and child’s sensory profiles. A quantitative, cross sectional study design established the sensory profiles of 81 children and their parents. Results indicated a moderate probability that a child with SMD may have a parent with SMD. A moderate to high probability existed for a parent with SMD to have a child with SMD. This supports the supposition that there is a hereditary component to SMD, with learned sedentary behavioural patterns. The treatment implications include considering the parent’s reaction to their own sensory thresholds and the influence this has on the child’s treatment and learnt behaviour.

碩士
國立臺灣科技大學
資訊工程系
96
Frequent pattern and association rule mining are popular topics in data mining. With the advance of these techniques, privacy issues attract more and more attentions in recent years. In this field, previous works hide sensitive information based on a uniform support threshold or using a privacy disclosure threshold. However in practical applications, we probably need to apply different support thresholds on different itemsets to reflect their significance. In this study, two sanitization frameworks, TBF and GTBA, are proposed to protect sensitive patterns and sensitive association rules with the concept of non-uniform sensitive thresholds, respectively. Based on different sensitive thresholds, the hiding result is closer to user requirements and real applications. Besides, the strategy of choosing rules, victim items, and victim transactions are proposed to preserve more information of the original dataset. In addition, we apply hash table, inverted file and some index skills to speed up the whole sanitization process. As shown in the experimental results, our frameworks can protect sensitive knowledge well not only under multiple thresholds but also a uniform threshold. Furthermore, these frameworks preserve more information, and reach higher similarity between the original dataset and the modified dataset. Moreover, the efficiency and the scalability can also be maintained.

The utilization of in vitro tests with a tiered testing strategy for detection of mild ocular irritants can reduce the use of animals for testing, provide mechanistic data on toxic effects, and reduce the uncertainty associated with dose selection for clinical trials. The first section of this thesis describes how in vitro methods can be used to improve the prediction of the toxicity of chemicals and ophthalmic products. The proper utilization of in vitro methods can accurately predict toxic threshold levels and reduce animal use in product development. Sections two, three and four describe the development of new sensitive in vitro methods for predicting ocular toxicity. Maintaining the barrier function of the cornea is critical for the prevention of the penetration of infections microorganisms and irritating chemicals into the eye. Chapter 2 describes the development of a method for assessing the effects of chemicals on tight junctions using a human corneal epithelial and canine kidney epithelial cell line. In Chapter 3 a method that uses a primary organ culture for assessing single instillation and multiple instillation toxic effects is described. The ScanTox system was shown to be an ideal system to monitor the toxic effects over time as multiple readings can be taken of treated bovine lenses using the nondestructive method of assessing for the lens optical quality. Confirmations of toxic effects were made with the utilization of the viability dye alamarBlue. Chapter 4 describes the development of sensitive in vitro assays for detecting ocular toxicity by measuring the effects of chemicals on the mitochondrial integrity of bovine cornea, bovine lens epithelium and corneal epithelial cells, using fluorescent dyes. The goal of this research was to develop an in vitro test battery that can be used to accurately predict the ocular toxicity of new chemicals and ophthalmic formulations. By comparing the toxicity seen in vivo animals and humans with the toxicity response in these new in vitro methods, it was demonstrated that these in vitro methods can be utilized in a tiered testing strategy in the development of new chemicals and ophthalmic formulations.

Doctor of Philosophy
Department of Geography
John A. Harrington Jr
The climate of the Middle East is warming and extreme hot temperature events are becoming more common, as observed by the significant upward trends in mean and extreme temperatures during the last few decades. Climate modeling studies suggest that the frequency, intensity, and duration of extreme temperature events are expected to increase as the global and local climate continues to warm. Existing literature about heat waves (HWs) in Saudi Arabia provides information about HW duration using a single index, without considering the observed effects of climate change and the subtropical arid climate. With that in mind, this dissertation provides a series of three stand-alone papers evaluating temporal, geographic, and atmospheric aspects of the character of warm season (May-September) HWs in Saudi Arabia for 1985 to 2014. Chapter 2 examines the temporal behavior(s) of the frequency, duration, and intensity of HWs under the observed recent climate change. Several issues are addressed including the identification of some improved methodological practices for HW indices. A time-sensitive approach to define and detect HWs is proposed and assessed. HW events and their duration are considered as count data; thus, different Poisson models were used for trend detection. Chapter 3 addresses the spatio-temporal patterns of the frequency and intensity of hot days and nights, and HWs. The chapter reemphasizes the importance of considering the on-goings effects of climate warming and applies a novel time-series clustering approach to recognize hot temperature event behavior through time and space. Chapter 4 explores the atmospheric circulation conditions that are associated with warm season HW event occurrence and how different HWs aspects are related to different circulation types. Further, possible teleconnections between HWs and sea surface temperature (SST) anomalies of nearby large bodies are examined. Results from Chapters 2 and 3 detected systematic upward trends in maximum and minimum temperatures at most of the 25 stations, suggesting an on-going change in the climatology of the upper-tail of the frequency distribution. The analysis demonstrated the value of using a time-sensitive approach in studying extreme thermal events. Different patterns were observed over time and space not only across stations but also among extreme temperature events (i.e., hot days and nights, and HWs). The overall results suggest that not only local and regional factors, such as elevation, latitude, land cover, atmospheric humidity, and distance from a large body of water, but also large-scale factors such as atmospheric circulation patterns are responsible for the observed temporal and spatial patterns. Chapter 4 confirmed that as the Indian Summer Monsoon Trough and the Arabian heat low were key atmospheric features related to HW days. SST anomalies seemed to be a more important factor for HWs intensity. Extreme thermal events in Saudi Arabia tended to occur during regional warming due to atmospheric circulation conditions and SSTs teleconnections. This study documents the value of a time-sensitive approach and should initiate further research as some of temporal and spatial variabilities were not fully explained