Browsing by Author "Park, Sun Young"
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Item A study on diagnostic image analysis for the detection of precancerous lesions using multi-spectral digital images(2007) Park, Sun Young; Richards-Kortum, Rebecca, 1964-; Markey, Mia KathleenThis dissertation explores a diagnostic image analysis framework using multispectral digital colposcopy for real-time in vivo detection of cervical cancer. In the first part of the dissertation, the clinical feasibility of a previously developed multispectral digital colposcope (MDC) is demonstrated using a hamster cheek pouch model of carcinogenesis. Various studies on MDC applications to cervical cancer detection in human subjects are then presented. First, an automated diagnostic image analysis algorithm for cervical cancer using white light reflectance images is presented. The algorithm can identify pre-neoplastic tissue areas from an entire cervix based on intensity changes feature in the reflectance images induced by acetic acid treatment. Then, the information about tissue type is incorporated into the diagnostic image analysis framework. For this purpose, a Markov Random Field (MRF) model is adopted and the results are discussed. One of the practical difficulties of utilizing a MRF model in unpolarized white light reflectance imaging is the specular reflection problem since the effect of specular reflection extends into surrounding tissue areas. Through the use of cross polarized imaging, the effects of specular reflection reduced and the ability to segment images based on tissue types is enhanced, leading to better diagnostic performance. The diagnostic performance of polarized imaging is compared to that of unpolarized imaging. In order to assess the performance of the proposed approach, a gold standard for the entire cervical image is constructed using histopathology results from a whole cervix specimen. The results presented in this dissertation indicate that an automated diagnostic image analysis framework for early detection of cervical cancer has the potential to be clinically applied as a low cost alternative screening technique in developing countries. Advances in imaging technology as well as in image analysis algorithms will continue to reduce the cost of diagnostic imaging systems and improve the imaging and diagnostic capability, leading to an inexpensive, real-time, minimally-invasive alternative to conventional screening techniques for early detection of cervical cancer in developing countries.Item Tapping the invisible market: the case of the cruise industry(2009-06-02) Park, Sun YoungThe definition of business success has evolved from winning larger market share in fierce competition to creating one?s own markets. Exploring new markets is crucial especially for tourism businesses, as one of the basic motives for leisure travel is seeking new or different experiences. Nonetheless, current non-customers have rarely been studied in the context of tourism. Using the cruise industry as a case, the first purpose of this study was to enhance the understanding of current non-customers (i.e., ?the invisible market?). Current noncustomers of the cruise industry were defined as leisure travelers who take other leisure vacation types, but have not taken a cruise vacation in the last five years (i.e., pastcruisers) or have never taken a cruise vacation (i.e., non-cruisers). The second purpose was to propose practical approaches for the cruise industry to utilize to tap the invisible market based on the findings. This study consists two phases using a sequential study design. In Phase 1, 22 guided conversations were conducted with people with and without cruise experiences using a modified Zaltman Metaphor Elicitation Technique to explore their images of cruise vacations. The findings suggested that current non-customers had different images of cruise vacations than current customers. In Phase 2, a conceptual model was developed based on the findings of Phase 1 and the literature on destination image and choice, the Model of Goal-directed Behavior and the leisure constraints model. Eleven hypotheses were tested with data collected from a survey of U.S. leisure travelers using descriptive statistics and structural equation modeling. Most relationships (e.g., directions and valence) among constructs were found to be in accordance with previous studies. Further, results suggested that current non-customers were more similar to than different from current customers in terms of socio-demographics and general vacation behavior. However, results implied that current non-customers? biases or negative images of cruise vacations could be the underlying factors that influence their decisions not to choose cruise vacations over other leisure vacation types. Practical recommendations for innovative marketing strategies are presented for the cruise industry.