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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Customer Rewards Programs : Designing Incentives for Repeated Purchase

Sällberg, Henrik January 2010 (has links)
Firms have since long given their regular customers special treatment. With the help of IT, many firms have established formal ways to do this. An example is a so-called customer rewards program (CRP), by which the firm rewards the customer for repeated purchase. Firms allocate large resources in these programs with millions of customers enrolled. Hence, it seems important that the CRP works effectively. By effective we mean that it increases sales. Whether it is effective or not is a matter of how it is designed. A CRP typically comes with membership levels. We study how many membership levels the firm should offer in an effective program. We also study if customers prefer individual or group rewards and whether a CRP can break and create habitual purchasing behavior. In the study, we also analyze under what conditions the customer prefers a CRP over a sales promotion. In general, the study adds to the understanding of Customer Rewards Programs as an incentive structure. There are many different ways to design these incentives and especially the continuing development of IT is expected to influence the future design and role of these types of programs. This study is part of the Swedish Research School of Management and Information Technology (MIT) which is one of 16 national research schools supported by the Swedish Government. MIT is jointly operated by the following institutions: Blekinge Institute of Technology, Gotland University College, Jönköping International Business School, Karlstad University, Linköping University, Lund University, Mälardalen University College, Stockholm University, Växjö University, Örebro University, IT University of Göteborg, and Uppsala University, host to the research school. At the Swedish Research School of Management and Information Technology (MIT), research is conducted, and doctoral education provided, in three fields: management information systems, business administration, and informatics.
112

Assessment and strengthening of ASR and DEF affected concrete bridge columns

Talley, Kimberly Grau 23 October 2009 (has links)
Alkali silica reaction (ASR) and delayed ettringite formation (DEF) are two causes of concrete deterioration. Both mechanisms cause expansion of concrete and thus extensive cracking. Most previous research on ASR and DEF focused on understanding the material science of the mechanisms. This dissertation adds to the smaller body of knowledge about ASR/DEF’s effect on the structural behavior of reinforced concrete columns. It compares the structural performance of ASR/DEF affected concrete columns to mechanically cracked columns, evaluates the relative performance of four different concrete repair methods for strengthening damaged columns, and describes how to model pre-existing cracks in the finite element program ATENA. Previous research on scaled columns used mechanically cracked concrete as an approximation of ASR/DEF cracking damage. These earlier column tests, by Kapitan, were compared to two columns affected by ASR/DEF. Due to a deficiency in original design of the actual columns modeled, all of these scaled column specimens failed in bearing during testing under biaxial bending. The ASR/DEF affected columns exhibited nearly identical performance (including bearing capacity) as Kapitan’s control specimen. Thus, with over one percent expansion due to ASR/DEF, there was no reduction in bearing capacity for these columns. Based on the bearing failure observed in these scaled column specimens, concrete repairs were designed to increase confinement of the column capital to address the bearing capacity deficiency. A series of bearing specimens was constructed, externally reinforced using four different strengthening schemes, and load tested. From this bearing specimen series, both an external post-tensioned repair and a concrete jacketing repair performed well beyond their designed capacities and are recommended for bearing zone confinement repair of similar ASR/DEF affected concrete columns. Further, this dissertation presents how Kapitan’s scaled column results were modeled using ATENA (a reinforced concrete finite element program). A technique for modeling the mechanical cracking was developed for ATENA. Once calibrated, a parametric study used the model to find that a 0.17-inch wide through-section crack in the scaled columnd (5/8 inches in the field) was the threshold that reduced capacity of the scaled column to the factored design load. / text
113

Implications of plasticization on the properties of hot-melt extruded oral dosage forms

Schilling, Sandra Ursula 27 May 2010 (has links)
The influence of plasticization and other formulation factors on the properties of hot-melt extruded dosage forms for the controlled release of water-soluble active compounds was investigated. Citric acid monohydrate was demonstrated to function as a solid-state plasticizer in hot-melt extruded Eudragit® RS PO tablets and in cast films when concentrations below the compatibility limit were employed. Melting of the organic acid and solubilization in the polymer during extrusion were necessary to observe the plasticizing effect. The release rate of diltiazem hydrochloride, used as a high-melting, water-soluble model drug, from melt extruded Eudragit® RS PO matrix tablets increased and became independent of the original drug particle size in the presence of citric acid monohydrate. Thermal analysis of physical mixtures demonstrated that citric acid promoted drug melting during extrusion by interaction and melting point depression. Diltiazem hydrochloride remained amorphous in the final dosage form, and leaching of citric acid monohydrate enhanced drug diffusion by increasing the matrix porosity. Delayed-release matrix pellets with particle sizes below one mm were prepared by hot-melt extrusion, and the influence of the matrix forming polymer and the type and level of plasticizer on the processibility and release properties was investigated. Pellets complied with the USP requirement for delayed release articles to release less than 10% drug at pH 1.2 after 2 hours when plasticized Eudragit® S100 was used as the release-controlling material. High levels of efficient plasticizers had to be employed to decrease the polymeric melt viscosity, increase the process yield and enable extrusion at moderate temperatures to avoid instabilities during processing and storage. The aqueous solubility of the plasticizer further impacted the drug release rate in acid. A novel application of hot-melt extrusion for the preparation of monolithic matrices comprising enteric coated particles was studied. The influence of the mechanical strength of the multiparticulates, pellet loading and nature of the hydrophilic carrier material on the preservation of the delayed-release properties after extrusion was investigated. Soft particles coated with brittle films remained intact when low-melting carriers that did not solubilize the enteric film during extrusion were used, and the dissolution profile was stable over one year. / text
114

ASR/DEF-damaged bent caps: shear tests and field implications

Deschenes, Dean Joseph 08 September 2010 (has links)
Over the last decade, a number of reinforced concrete bent caps within Houston, Texas have exhibited premature concrete damage (cracking, spalling and a loss of material strength) due to alkali-silica reaction (ASR) and/or delayed ettringite formation (DEF). The alarming nature of the severe surface cracking prompted the Houston District of the Texas Department of Transportation to initiate an investigation into the structural implications of the premature concrete damage. Specifically, an interagency contract with the University of Texas at Austin charged engineers at Ferguson Structural Engineering Laboratory to: 1. Establish the time-dependent relationship between ASR/DEF deterioration and the shear capacity of affected bridge bent caps. 2. Develop practical recommendations for structural evaluation of in-service bridge bent caps affected by ASR and/or DEF. To accomplish these objectives, six large-scale bent cap specimens were fabricated within the laboratory. Four of the specimens (containing reactive concrete exposed to high curing temperatures) represented the most severe circumstances of deterioration found in the field. The remaining two specimens (non-reactive) provided a basis for the comparison of long-term structural performance. All of the specimens were subjected to a conditioning regimen meant to foster the development of realistic ASR/DEF-related damage. Resulting expansions were characterized over the course of the study through a carefully-planned monitoring program. Following a prolonged exposure period, three of the six bent cap specimens (representing undamaged, mild, and moderate levels of deterioration) were tested in shear. Observations made over the course of each test captured the service and ultimate load effects of ASR/DEF-induced deterioration. Six shear-critical spans were tested prior to this publication: three deep beam and three sectional shear tests. The remaining six shear spans (contained within the remaining three specimens) were retained to establish the effects of severe deterioration through future shear testing. Subsequent analysis of the expansion monitoring and shear testing data provided much needed insight into the performance and evaluation of ASR/DEF damaged bent structures. The results ultimately formed a strong technical basis for the preliminary assessment of a damaged bent structure within Houston, Texas. / text
115

The validity of a three-part criteria for differentiating between delayed pharyngeal swallow and premature spillage secondary to poor oro-lingual control on videofluoroscopy

Flanagan, Liana January 2007 (has links)
Background and Aims The accurate differentiation between a delayed pharyngeal swallow (sensory impairment) and premature spillage secondary to poor oro-lingual control (motor impairment) is essential to effective dysphagia management. However both physiologic abnormalities result in an identical radiographic sign, that of pre-swallow pooling of the bolus in the pharynx. The dysphagia literature does not provide satisfactory guidelines for making this distinction on videofluoroscopy. The purpose of this study was to assess the validity of a three-part rating scale for differentiating between these two impairments. Methods Videofluoroscopy was used to evaluate the swallowing of 29 participants presenting with dysphagia following stroke. Sensory thresholds for these participants were established by electrical stimulation of the anterior faucial pillars. The videofluoroscopic swallowing studies were analysed using the three-part rating scale and results from this were compared to sensory thresholds using Pearson's product moment correlation. Results There was no significant correlation between the three-part criteria and sensory thresholds. Inter-rater reliability for some measures was poor. Conclusions The three-part criteria was not shown to be a valid measure for differentiating between delayed pharyngeal swallow and premature spillage secondary to poor oro-lingual control. Possible explanations for these findings are discussed, including the relevance of faucial pillar sensation to swallowing.
116

Stochastic Analysis of Pumping Tests in Unconfined Aquifers

Mao, Deqiang January 2012 (has links)
The S shaped log log drawdown time curve typical of pumping tests in unconfined aquifers is reinvestigated via numerical experiments. We examine the temporal and spatial evolution of the rate of change in storage in an unconfined aquifer during pumping. This evolution is related to the transition of water release mechanisms from the expansion of water and compaction of the porous medium to the drainage of water from the unsaturated zone above the initial water table and initially saturated pores as the water table falls during the pumping of the aquifer. We conclude that the transition of the water release mechanisms and vertical flow are the cause of the S shaped drawdown time. Cross-correlation analysis is then employed to examine the relationship between hydraulic properties of an unconfined aquifer and pressure observations. The analysis reveals that head observed in the saturated zone at late times along a streamline is positively correlated with the conductivity (K(s)) of the region upstream of the observation location, and negatively correlated with the K(s) of the region downstream of the observation location along the same streamline. Besides, head observations in the saturated zone at the early time are positively correlated with specific storage (S(s)) in a narrow region between the observation and pumping locations. At intermediate and late times, the head positively correlates with the heterogeneity of α (pore-size distribution parameter) in a thin disk-shaped unsaturated region above the pumping and observation locations. Saturated water content θ(s) in the vadose zone directly above the pumping and monitoring locations is found positively correlated with the head observations during the intermediate times and late times.In the end, a stochastic inverse estimation is conducted to jointly interpret a sequential pumping test in a three dimensional unconfined aquifer. K(s), S(s), θ(s) and α are estimated at the same time. The estimated results capture the pattern of the heterogeneous parameters as well as the details with a smooth distribution. The estimated heterogeneous parameter fields produce better head predictions than the traditional homogeneous method.
117

Quantum States as Objective Informational Bridges

Healey, Richard 09 September 2015 (has links)
A quantum state represents neither properties of a physical system nor anyone s knowledge of its properties. The important question is not what quantum states represent but how they are used as informational bridges. Knowing about some physical situations (its backing conditions), an agent may assign a quantum state to form expectations about other possible physical situations (its advice conditions). Quantum states are objective: only expectations based on correct state assignments are gen- erally reliable. If a quantum state represents anything, it is the objective probabilistic relations between its backing conditions and its advice con- ditions. This paper o¤ers an account of quantum states and their function
118

The Effects of Positive and Negative Experiences on Subsequent Behavior and Cognition in Capuchin Monkeys (Cebus Apella)

Smith, Mackenzie F 03 May 2017 (has links)
While it is known that acute and chronic stress can impact cognition, less is known about the immediate impacts of minor frustrations or positive experiences on subsequent behavior and cognition in primates. This study used a novel methodology to engineer both a positive and (slightly) frustrating experience, using the same apparatus, in 15 adult capuchin monkeys. Subjects were presented with a working memory task (DMTS) for 30 minutes after the experimental manipulations (or a control). As predicted, the frustrating task prior to testing resulted in a decrease in performance on the DMTS compared to performance after a positive experience or the control. Contrary to predictions, a positive experience did not facilitate performance to higher levels than the control condition. Manipulations also impacted several behaviors. Although there may be different results in different contexts, these results indicate that even mild negative experiences impact subsequent behavior and cognition in primates.
119

Delayed Sleep Phase Disorder : Prevalence, Diagnostic aspects, Associated factors and Treatment concepts

Danielsson, Katarina January 2016 (has links)
Delayed sleep phase disorder (DSPD) is the most common circadian rhythm sleep disorder. Persons with DSPD have great difficulties falling asleep and waking up at conventional times. To diagnose DSPD this delayed sleep-wake rhythm should cause social impairment and distress for the individual. Evening melatonin and morning bright light are the recommended treatments. The overall aim of this thesis was to evaluate at-home treatment with Light therapy (LT) and the feasibility of adding cognitive behavior therapy (CBT) to LT in DSPD, furthermore prevalence, diagnostic aspects and associated factors were investigated. Study I included 673 randomly selected individuals aged 16–26 years. The prevalence of DSPD was 4.0%. Unemployment (defined as an absence of educational or work activities) and an elevated level of anxiety were associated with DSPD. In study II, dim light melatonin onset (DLMO) was measured in healthy adults. Time for DLMO DLMO (Mean±SD) was 20:58±55 minutes. Studies III, IV, and V present results from a randomized controlled trial examining the feasibility of CBT as an additive treatment to LT with scheduled rise times, in persons with DSPD. Sleep onset and sleep offset was significantly advanced from baseline (03:00±1:20; 10:22±2:02 respectively) to the end of LT (01:27±1:41; 08:05±1:29, p<0.001 respectively). This advancement was predicted by consistent daily usage of the LT-lamp. At the follow-ups after LT and CBT or LT alone, sleep onset remained stable, sleep offset was delayed, and sleep difficulties were further improved, but there was no significant group interaction over time. There was a significant group interaction over time in the severity of anxiety and depressive symptoms, both in favor of the LT+CBT group. Conclusively, DSPD was common among adolescents and young adults and it was associated with unemployment and elevated levels of anxiety. DLMO appeared in the expected time range in healthy working adults. At-home treatment with LT with scheduled rise times advanced sleep-wake rhythm and improved sleep difficulties in DSPD. Even though sleep-wake rhythm was not further advanced or better preserved in the participants that received LT+CBT compared to LT alone, the addition of CBT to the treatment regimen was feasible and well accepted.
120

Failed noninvasive positive-pressure ventilation is associated with an increased risk of intubation-related complications

Mosier, Jarrod M, Sakles, John C, Whitmore, Sage P, Hypes, Cameron D, Hallett, Danielle K, Hawbaker, Katharine E, Snyder, Linda S, Bloom, John W 06 March 2015 (has links)
UA Open Access Publishing Fund / Background: Noninvasive positive-pressure ventilation (NIPPV) use has increased in the treatment of patients with respiratory failure. However, despite decreasing the need for intubation in some patients, there are no data regarding the risk of intubation-related complications associated with delayed intubation in adult patients who fail NIPPV. The objective of this study is to evaluate the odds of a composite complication of intubation following failed NIPPV compared to patients intubated primarily in the medical intensive care unit (ICU). Methods: This is a single-center retrospective cohort study of 235 patients intubated between 1 January 2012 and 30 June 2013 in a medical ICU of a university medical center. A total of 125 patients were intubated after failing NIPPV, 110 patients were intubated without a trial of NIPPV. Intubation-related data were collected prospectively through a continuous quality improvement (CQI) program and retrospectively extracted from the medical record on all patients intubated on the medical ICU. A propensity adjustment for the factors expected to affect the decision to initially use NIPPV was used, and the adjusted multivariate regression analysis was performed to evaluate the odds of a composite complication (desaturation, hypotension, or aspiration) with intubation following failed NIPPV versus primary intubation. Results: A propensity-adjusted multivariate regression analysis revealed that the odds of a composite complication of intubation in patients who fail NIPPV was 2.20 (CI 1.14 to 4.25), when corrected for the presence of pneumonia or acute respiratory distress syndrome (ARDS), and adjusted for factors known to increase complications of intubation (total attempts and operator experience). When a composite complication occurred, the unadjusted odds of death in the ICU were 1.79 (95% CI 1.03 to 3.12). Conclusions: After controlling for potential confounders, this propensity-adjusted analysis demonstrates an increased odds of a composite complication with intubation following failed NIPPV. Further, the presence of a composite complication during intubation is associated with an increased odds of death in the ICU.

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