The United States generated approximately 730kg of waste per capita in 2013, which is the highest amount of waste among OECD countries. The waste has adverse effects to human health and the environment. One of the most serious adverse effects is greenhouse gas emissions, especially methane (CH4), which causes global warming. However, the United States' amount of waste generation is not decreasing, and the recycling rate is only 26%, which is lower than other OECD countries. In order to decrease waste generation and greenhouse gas emissions, identifying the causality of the waste generation and greenhouse gas emissions from waste sector should be made a priority. The research objective is to verify whether the Environmental Kuznets Curve relationship is supported for waste generation and GDP across the U.S. Moreover, it also confirmed that total waste generation and recycling of waste influences carbon dioxide emissions from the waste sector. Based on the results, critical insight and suggestions were offered to policymakers, which is the potential way to lower the solid waste and greenhouse gas emissions from the waste sector. This research used annually based U.S. data from 1990 to 2012, and these data were collected from various data sources. To verify the causal relationship, the Granger causality test was applied. The results showed that there is no causality between GDP and waste generation, but total waste and recycling generate significantly increasing and decreasing greenhouse gas emissions from the waste sector, respectively. This implies that waste generation will not decrease even if GDP increases. And, if waste generation decreases or the recycling rate increases, greenhouse gas emission will decrease. Based on these results, increasing the recycling rate is first suggested. The second suggestion is to break the causal relationship between MSW and greenhouse gas emission from the waste sector. The third is that the U.S. government should benchmark a successful case of waste management. Based on the research, it is expected that waste generation and carbon dioxide emission from the waste sector can be decreased more efficiently.

Building energy systems are designed to handle both permanent and temporary occupants. Permanent occupants are considered the base energy load while temporary occupants are considered a temporary or additional load. Temporary occupancy is potentially the most difficult to design as the number of temporary occupants varies more significantly than permanent occupants. This case study was designed to investigate the effect of occupancy on energy loads, i.e. the relationship between occupancy and building energy loads. This study estimated the building occupancy by using existing network infrastructure, such as Wi-Fi and wired Ethernet based on the assumption that the number of Wi-Fi connections and the wired Ethernet traffic were used as a proxy for total and stationary occupancy. The relationships were then examined using correlations and regression analyses. The results showed the following: 1. Stationary occupancy was successfully estimated using the network infrastructure; 2. There was a linear relationship between electricity use and total occupancy (and, thus, the use of network infrastructure); 3. Permanent occupants generated a higher impact on the electricity load than the temporary occupants; 4. There was a logarithmic relationship between electricity use and the Ethernet data traffic (a proxy of permanent occupants); and 5. The statistical and qualitative analyses indicated that there was no significant relationship between occupancy and thermal loads, such as cooling and heating loads.

Modular construction techniques can not only significantly contribute to improved project cost, schedule, and quality performance, but also sustainability by reducing site disruption and waste generated, creating better relocatability and reusability. However, there are still difficulties in developing and implementing modularization in a hospitality centric environment. Thus, the primary goal of this research is to identify the opportunities and challenges of implementing sustainable modular construction techniques in a hospitality-centric environment. In this study, the approach includes the formulation of a survey, which was distributed to 600 industry professionals in Las Vegas and completed by 63 industry professionals, followed by three personal interviews. The results showed that: 1) 85% percent of survey participants expected an improvement in schedule, and 65% of that elected to use a form of modularization actually experienced an improved schedule; 2) 62% of the participants claimed that they would keep using modular methods in the next 12 months, whereas 44% of the participants claimed they would increase their use of modularization in the next five years; 3) two of the top five expected benefits achieved included less site disruption (noise/traffic and dust) and reduced waste, which contribute towards sustainable construction; 4) transportation/logistics was selected by industry professionals as a key barrier in the implementation of modular construction; 5) to implement more sustainable construction, practitioners require additional research to improve and overcome the key barrier of transportation/logistics; 6) if construction professionals gain more modular project experience, their perceived benefits and barriers could increase and decrease, respectively. The results from this research provide valuable insights for implementing sustainable modular methods in hospitality-centric environments.