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Full-Text Articles in Social and Behavioral Sciences

On The Test Accuracy And Effective Control Of The Covid-19 Pandemic: A Case Study In Singapore, Guang Cheng, Sarah Yini Gao, Yancheng Yuan, Chenxiao Zhang, Zhichao Zheng Mar 2022

On The Test Accuracy And Effective Control Of The Covid-19 Pandemic: A Case Study In Singapore, Guang Cheng, Sarah Yini Gao, Yancheng Yuan, Chenxiao Zhang, Zhichao Zheng

Research Collection Lee Kong Chian School Of Business

This study examines the impact of coronavirus disease 2019 (COVID-19) test accuracy (i.e., sensitivity and specificity) on the progression of the pandemic under two scenarios of limited and unlimited test capacity. We extend the classic susceptible–exposed–infectious–recovered model to incorporate test accuracy and compare the progression of the pandemic under various sensitivities and specificities. We find that high-sensitivity tests effectively reduce the total number of infections only with sufficient testing capacity. Nevertheless, with limited test capacity and a relatively high cross-infection rate, the total number of infected cases may increase when sensitivity is above a certain threshold. Despite the potential for …


A Constraint Programming Approach To Load Capacity Planning In Container Vessels, Byung Kwon Lee, Joyce M. W. Low Feb 2022

A Constraint Programming Approach To Load Capacity Planning In Container Vessels, Byung Kwon Lee, Joyce M. W. Low

Research Collection Lee Kong Chian School Of Business

A container vessel carries containers of various characteristics, in terms of size, weight, and contents. The cargo load of a container vessel, being subjected to a set of operational conditions and restrictions regarding ship stability and safety, is a fundamental element in decision-making when a shipping line provides logistics services to clients. This study presents a constraint programming-based model for the capacity planning of a container vessel under various operational conditions. The proposed model generates base solutions and is complemented with a rich scenario-based analysis that utilizes real-life ship data of a container vessel operated by a liner shipping company …


The Moderating Effect Of Solar Radiation On The Association Between Human Mobility And Covid-19 Infection In Europe, Wenyu Zhao, Yongjian Zhu, Jingui Xie, Zhichao Zheng, Haidong Luo, Oon Cheong Ooi Jan 2022

The Moderating Effect Of Solar Radiation On The Association Between Human Mobility And Covid-19 Infection In Europe, Wenyu Zhao, Yongjian Zhu, Jingui Xie, Zhichao Zheng, Haidong Luo, Oon Cheong Ooi

Research Collection Lee Kong Chian School Of Business

The novel coronavirus disease 2019 (COVID-19) has caused a global pandemic. Some studies have suggested a negative association between sunlight intensity and COVID-19 infection, alluding to the belief that it might be safe to go out on sunny days. This paper examined whether solar radiation mitigated the association between human mobility and COVID-19 infection in Europe using a dynamic panel data model to investigate the effect of human mobility, solar radiation, and their interaction on COVID-19 infection. The results revealed that outgoing mobility was positively correlated and solar radiation was negatively correlated with COVID-19 infection at lag levels of 1, …


Schedule Reliability In Liner Shipping Timetable Design: A Convex Programming Approach, Abraham Zhang, Zhichao Zheng, Chung-Piaw Teo Jan 2022

Schedule Reliability In Liner Shipping Timetable Design: A Convex Programming Approach, Abraham Zhang, Zhichao Zheng, Chung-Piaw Teo

Research Collection Lee Kong Chian School Of Business

Container liner shipping is the primary mode of moving manufactured products across continents. Partly due to inherent uncertainties at sea and ports, the liner shipping industry has long had a notorious reputation of schedule delays and unreliable on-time performance. This paper formulates a new approach to incorporate schedule reliability targets in liner shipping timetable design, to balance bunker consumption, time taken for the voyage, and schedule delays. We first model a surrogate problem using a copositive program through a moment decomposition approach and solve it as a convex semidefinite programming relaxation. We next incorporate schedule reliability targets implicitly by exploiting …