Browsing by Author "Chen, Wei-Ting"

Now showing 1 - 10 of 10

A mathematical programming model for aircraft leasing decisions
(2018-06-01)
Chen, Wei-Ting
;
Huang, Kuancheng
;
Ardiansyah, Muhammad Nashir
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
For the airline fleet planning problem, this paper formulates a mathematical programming model specifically also taking into account of the increasingly popular capital lease, which has some mixed features of the two traditional aircraft acquirement methods: operating lease and purchase. Given the aircraft requirements, budget, and debt-ratio limit, the objective is to minimize the total cost within the planning horizon. Numerical experiments were conducted to compare the optimal solutions for the airlines with different business models, scales, and experiences. This paper further simulates a scenario under the new standards which will be applied in 2019. The results of sensitivity analysis show that when the debt-ratio constraint is relaxed, capital leases would be helpful for reducing the cost of airlines.
A study of caprolactam storage tank accident through root cause analysis with a computational approach
(2017-11-01)
Liu, Wei-Yi
;
Chen, Chiun-Hsun
;
Chen, Wei-Ting
;
Shu, Chi-Min
;
機械工程學系
In Taiwan, the rapid development of the petrochemical industry over the past four decades has resulted in economic progress and technological advancement. However, this success has been accompanied by pollution and sporadic accidents. Numerous accidents related to crude oil and its derivatives have resulted in a loss of life, employee injuries, environmental and property damage, economic decay, social outcry, and even political turmoil. This study investigated a caprolactam storage tank accident through root cause analysis with a computational approach. The previously described approaches returned findings that indicated causes similar to the real cause of this caprolactam accident. The four summarized descriptions of false conditions of the caprolactam explosion can serve as a reference for other investigations into the causes of petrochemical accidents. Reason of the caprolactam storage tank accident was determined by root cause analysis accompanying with a computational approach. (C) 2017 Elsevier Ltd. All rights reserved.
A study on airlines' differentiated cargo service strategies
(2013-01-01)
Hsu, Chaug-Ing
;
Chen, Yu-Hua
;
Chen, Wei-Ting
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
This study analyzes how an airline operates differentiated cargo services to meet shipping demand for different goods so as to enhance its service level, air freight demand, and total profit. The shipping alternative choice model assumes shippers with different demand characteristics choose the alternative with the lowest transportation and inventory costs between express and standard shipping services offered by different airlines. The study then formulates airline cost functions with respect to providing standard and express services. Furthermore, the study explores demand-supply interactions and constructs a mathematical programming model to determine flight frequencies and shipping charges for standard and express services by maximizing the object airline's total profit. The results show that those shipping high-value freights tend to select express shipping services and, for the object airline, operating differentiated cargo services rather than the current standard services can raise its market share and total profit by 19.4% and 8.6%, respectively. Moreover, for perishable goods stored in lower temperature-control devices, the charges should be higher. The results also show that not only airlines, but also shippers, can markedly reduce their costs and enhance their competitive advantages with express shipping services. (C) 2012 Elsevier Ltd. All rights reserved.
Fire suppression performance of water mist under diverse desmoking and ventilation conditions
(2020-01-01)
Liu, Wei-Yi
;
Chen, Chiun-Hsun
;
Shu, Yi-Liang
;
Chen, Wei-Ting
;
Shu, Chi-Min
This paper described full-scale tests of water mist fire suppression system under forced desmoking conditions. Pool fire was effectively suppressed in 25.0 and 37.0 s for 1,500.0 (test 1) and 3,000.0 (test 2) mL of oil with no ventilation, respectively. Moreover, under ventilation rates of 50.0 and 75.0 m(3)/min, the suppression time were lengthened to 54.0 s (test 1) and 202.0 s (test 2), and 102.0 s (test 1) and 222.0 s (test 2), correspondingly. However, the smoke exhaust had a strong effect on the water mist to result in fire could not extinguish, when the ventilation rate increased to 120.0 m(3)/min. The temperature distribution during the early period in the scenario of no ventilation has a higher magnitude than those scenarios of 50.0, 75.0, and 120.0 m(3)/min, because combustion proceeds smoothly to result in temperature increased rapidly at no ventilation. Furthermore, similar results presented in smoke concentration distribution at four scenarios (0, 50.0, 75.0, and 120.0 m(3)/min), and combustion occurred steadily at no ventilation to result in more smoke during the early period. This study employed a computer modeling to verify water mist system in a compartment space and determine how the water mist system could be optimized. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Generation of Octave-Spanning Multiple Harmonics for Ultrafast Waveform Synthesis
(2009)
Hsu, Wei-Chun
;
Hsieh, Zhi-Ming
;
Lai, Ying-Yao
;
Lai, Chien-Jen
;
Chen, Wei-Ting
Up to seven laser harmonics covering more than two octaves in frequency have been generated efficiently in a single PPLT crystal. permitting the syntehsis of 1.5 femtosecond pulses in a stable and compact setting
Greenhouse gas emission estimation for temperature-controlled food distribution systems
(2015-10-01)
Chen, Wei-Ting
;
Hsu, Chaug-Ing
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
Greenhouse gas (GHG) emissions from food transportation include emissions from energy consumption and refrigerant leakage into the environment. The hydrofluorocarbons (HFCs) and perflourocarbons (PFCs) generated by refrigerant leakage markedly increase global warming (GW). The issue of emissions from temperature-controlled food delivery is important for carriers. This paper aims to estimate GHG emissions from the Traditional Multi-Vehicle Distribution (TMVD) and Multi-Temperature Joint Distribution (MTJD) systems by formulating mathematical models that consider delivery scheduling for time-dependent demand of multi-temperature foods. Furthermore, this paper analyzes and compares the emissions from each source in the two systems to explore the influence of delivery scheduling on emissions. The results indicate that, as compared to the TMVD system, the MTJD system yields less total emissions by lowering fuel consumption even when it generates more GHG due to refrigerant leakage and electric power consumption for freezers, which accounts for an extremely low percentage of total emissions. This paper suggests carriers should use the MTJD system to reduce routing distances and emissions simultaneously. (C) 2015 Elsevier Ltd. All rights reserved.
Optimal delivery cycles for joint distribution of multi-temperature food
(2013-11-01)
Hsu, Chaug-Ing
;
Chen, Wei-Ting
;
Wu, Wei-Jen
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
The need for fresh, refrigerated, and frozen food has been continuously growing due to high demand for healthy and convenient diets in urban fast-paced daily living. Correspondingly, the market for low temperature logistics is expanding due to demand for low-temperature food, and the process of delivering food requiring storage and shipping in containers with different temperature ranges has become an important issue for carriers. This study analyzes optimal delivery cycles for jointly delivering multi-temperature food using Traditional Multi-Vehicle Distribution and Multi-Temperature Joint Distribution systems. We formulate mathematical models for the systems considering a variety of time-dependent demands and time-windows for delivering different temperature range foods to various customers. The models provide effective tools that determine delivery cycles and dispatching lists for carriers. The results show both carriers and shippers benefit from jointly delivering different temperature range foods using a single vehicle to ensure the freshness of the food. (C) 2013 Elsevier Ltd. All rights reserved.
Optimizing fleet size and delivery scheduling for multi-temperature food distribution
(2014-02-01)
Hsu, Chaug-Ing
;
Chen, Wei-Ting
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
In light of the demand for high-quality fresh food, transportation requirements for fresh food delivery have been continuously increasing in urban areas. Jointly delivering foods with different temperature-control requirements is an important issue for urban logistic carriers who transport both low temperature-controlled foods and normal merchandise. This study aims to analyze and optimize medium- and short-term operation planning for multi-temperature food transportation. For medium-term planning, this study optimizes fleet size for carriers considering time-dependent multi-temperature food demand. For short-term planning, this study optimizes vehicle loads and departure times from the terminal for each order of multi-temperature food, taking the fleet size decided during medium-term planning into account. The results suggest that carriers determine departure times of multi-temperature food with demand-supply interaction and deliver food of medium temperature ranges with priority because delivering such food yields more profit. (C) 2013 Elsevier Inc. All rights reserved.
Pregnenolonyl-alpha-glucoside exhibits marked anti-cancer and CYP17A1 enzymatic inhibitory activities
(2020-02-07)
Chou, Feng-Pai
;
Hsu, Wen-Chen
;
Huang, Sheng-Cih
;
Chang, Chin-Yuan
;
Chiou, Ya-Sheng
We report here that pregnenolonyl-alpha-glucoside (2), a steryl glycoside synthesized directly from pregnenolone and glucose via a consecutive multienzyme-catalyzed process, exhibits marked dose-dependent cytotoxic activity against HT29, AGS, and ES-2 cells with IC50 values of 23.5 to 50.9 mu M. An in vitro CYP17A1 binding pattern assay and protein-ligand docking model support that 2, like abiraterone, binds in the active site heme iron pocket of CYP17A1.
Pressure effect on impurity local vibrational mode and phase transitions in n-type iron-doped indium phosphide
(2018-01-19)
Lin, Chih-Ming
;
Hsu, I-Jui
;
Lin, Sin-Cheng
;
Chuang, Yu-Chun
;
Chen, Wei-Ting
The evolution of iron local vibrational mode (Fe LVM) and phase transitions in n-type iron-doped indium phosphide (InP:Fe) were investigated at ambient temperature. In-situ angle-dispersive X-ray diffraction measurements revealed that InP: Fe starts to transform from zinc-blende (ZB) to rock-salt (RS) structure around 8.2(2) GPa and completes around 16.0(2) GPa. The Raman shift of both transverse and longitudinal optical modes increases monotonically with increasing pressure, while their intensities become indiscernible at 11.6(2) GPa, suggesting that the pressure-induced phase transition is accompanied by significant metallization. In contrast, originally absent at ambient pressure, the Raman shift of Fe LVM appears at similar to 420 cm(-1) near 1.2 GPa and exhibits a dome shape behavior with increasing pressure, reaching a maximum value of similar to 440 cm-1 around 5 GPa, with an apparent kink occurring around the ZB-RS transition pressure of similar to 8.5(2) GPa. The Fe K-edge X-ray absorption near edge structure (XANES) confirmed the tetrahedral site occupation of Fe3+ with a crystal field splitting parameter Delta(t)=38k . mole(-1). Our calculations indicate that the energy parameters governing the phase transition are Delta(t)=0.49 and Delta(o) =1.10 kJ . mole(-1),respectively, both are much smaller than Delta(t) = 38 kJ . mole(-1) at ambient.