Shape design optimization of parametric flume sections.

This research presents a shape design analysis and optimization methodology for parametric surface flume sections. Flume sections or flow channels have been used widely in many areas such as water chutes in civil and agricultural engineering and water slides and bob sled tracks in the recreational and sports fields. Designing such a flow channel in a CAD environment can provide many advantages such as time and resource savings to the designer. In addition, optimizing such flow channels in a virtual environment is especially efficient.In this research, geometric modeling was addressed first. Two types of parametric surface flume section models were created: B-Spline-based flume sections and parametric CAD-based flume sections as used in water chutes or water slides. The B-Spline-based flume sections were based on the dimensions of fifteen flume sections, provided by a commercial water slide firm. These flume sections presented the basis for building up realistic flume section configurations. In addition, three different kinds of CAD-based flume sections were developed by the author. Sets of differential equations based on Lagrange's equations of motion were derived that describe the motion of an object traveling in the flow channel. These ordinary differential equations were solved using MathematicaRTM. Continuity requirements were derived from the equations of motion. An analytical shape design sensitivity analysis (DSA) methodology was developed and employed to support the optimization of the B-Spline-based and the CAD-based flume section models.Optimization of parametric surfaces is a reasonably new area. Although research has been done in this area, most of it has been focused on developing better parametric surfaces, i.e., surface fitting schemes. Here, the B-Spline-based models, based on bi-cubic B-Spline surfaces, were optimized first. The control point positions were used as design variables in the optimization. Using the B-Spline control points as design variables provides more flexibility and allows for local design changes. However, the fact that no CAD software provides the control points as design parameters significantly limits their usefulness in a real design environment. The CAD-based flume section models consisted of sets of key dimensions, which were again defined as design variables for optimization. Using dimensions as design variables provided an easy and realistic avenue for design changes. However, the limited number of dimensions also limits the flexibility of design changes in the CAD-based flume section models. (Abstract shortened by UMI.

KOREA OUTBOUND TOURISM TO SEVEN COUNTRIES: VAR MODEL AND GRANGER CAUSALITY TEST

This paper investigates the causal relationship among Korean outbound tourism demand for seven countries such as United States, China, Hong Kong, Japan, Philippines, Singapore, and Thailand. Since there are no long-run relationships among Korean outbound tourism demand for those international destinations the vector autoregressive (VAR) model is used for testing such causality. From the causality results, we found United States is leading country for Korean outbound tourism demand. When Korean tourism demands for United States increase, those for the other countries get a raise. Also, tourism demand for Thailand is influenced by tourism demands for three countries such as Hong Kong, Singapore and United States. Our results imply that government and managerial implications are recognized based on the empirical findings

Interrelationships Among Korean Outbound Tourism Demand:Granger Causality Analysis

This study investigated Korean outbound tourism demand and its determinants using the Granger causality (GC) analysis. In contrast to previous studies, which dealt only with internal factors, such as exchange rate and income, this study examined the effects of interactions among countries and, therefore, more complete and relevant results were found. Korean outbound tourism to the USA is causally related to Korean outbound tourism to the other six countries in this present study. These results can be applicable for the purpose of tourism marketing and strategies for industries and governments to allocate tourism resources more efficiently.This paper is forthcoming in Tourism Economics

Quantile Elasticity of International Tourism Demand for South Korea using Quantile Autoregressive Distributed Lag Model

This paper investigates international inbound tourism demand for South Korea and its determinants using quantile autoregressive model. In contrast to previous studies which dealt with only conditional mean, we examine effects of covariates at various conditional quantile levels; and therefore, more complete and interesting results are found. For inbound tourism demand, U.S. and Japanese tourism  demand are considered. For U.S. tourism demand, costs of living in Korea and competing destinations have moderate significant negative effects only at very high and low quantiles, while income does not have any significant effect to tourism demand. On the other hand, for Japanese tourism demand, income has significantly positive effects at lower quantiles, and living costs in Korea and competing destinations have significant negative effects at higher quantiles. These results address the heterogeneity in the tourism demand analysis.This paper has been accepted for publication to Tourism Economics

Does the strengthening of IPRs widen the growth gap?

This article builds a model of cumulative growth in order to analyze the relationship between intellectual property rights (IPRs) and economic growth in 38 countries from 1980 to 2005. The analysis focuses on the impacts of IPRs on the growth gap between countries using a catch-up model and USPTO database. The empirical results show that the strengthening of IPRs has a positive impact on innovation in developed and developing countries in Asia, while we fail to find evidence in Latin America. Secondly, similar to assertions made by De Long and Summers (1991) and Dowrick and Nguyen (1989), investment in fixed capital plays a critical role in growth gap dynamics. What needs to be emphasized here is the cumulative causal relationship between investment and growth: investment in fixed capital improves productivity and encourages economic growth thereby triggering even more investment. This paper confirms that the strengthening of IPRs and investment in fixed capital contribute to the widening of the economic development gap for the 1980–2005 period

Response of different cultivation substrates on the chilling injury symptom of sweet pepper grown in hydroponics

This study determined the chilling injury interactions of sweet peppers with their hydroponic growth substrate. The treatments were cocopeat, perlite, and a mixture of 50:50 cocopeat and perlite (coco-perlite). The fruits, when harvested, were stored for 50 days using the modified atmosphere package (MAP) at 5 °C. The results revealed no significant interactions between the growth substrate and the chilling injury indicators (respiration and ethylene production rates, electrolyte leakage, malondialdehyde), even though a significant interaction existed with the chilling injury index (a water-soaked area). This is believed to be due to the growth substrate’s significant interactions with soluble solids and dry matter, which aided cellular balance and increased chilling injury tolerance in perlite and coco-perlite treatment. Weight loss rate and firmness loss were insignificant in all treatments, and cocopeat treatment may be considered the worst of all treatments