Browsing by Author "Kim, Junghwan"

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    The Emergence of Lyme Disease in Appalachia (2000-2019)
    Otieno, Geoffrey Omondi (Virginia Tech, 2024-03-15)
    Emerging infectious diseases continue to threaten human health and healthcare resources across the world, and with the sustained emergence of some like Lyme disease, this trend is only expected to get worse. Even though some research has examined the spread of Lyme disease in different parts of the United States, focusing on its origin, spread, surveillance, and reporting, there has been minimal research on the recent spread of Lyme disease into and within Central and Southern Appalachia. This is an important gap, considering that this region is at the edge of the disease's expanding incidence and range. Considering this factor and the consequences that this disease may have on the residents of Appalachia who already face an array of underlying problems like chronic conditions, decreased access to health care, and exposure through outdoor work like resource extraction, addressing this gap will be important in understanding the current and future spatial range and impacts of the continued emergence of Lyme disease in Appalachia. This study thus sought to examine the extent of the emergence of Lyme disease in Appalachia between 2000 and 2019 using spatial scan statistic. This type of analysis uses spatiotemporal information to quantify disease emergence and diffusion using retrospective case and location data within a GIS environment; hence it helped quantify the spatial distribution and diffusion of Lyme disease into and within Appalachia and identify additional areas that can be targeted with public health prevention measures. We found five statistically significant clusters of Lyme disease across the contiguous US, indicating that the disease expanded spatially over the study period. Lyme disease has more than tripled across the US, with the number of counties with RR>1 increasing from 130 in 2000 to 453 by 2019. Lyme disease also increased more than eightfold in Appalachia, with spread southwards into and within Appalachia. The number of Appalachian counties with RR>1 increased from 16 in 2000 to 127 in 2019. These findings are important in understanding the current and future spatial range and the impacts of the continued emergence of Lyme disease in Appalachia. With this understanding, we can minimize the misdiagnosis of Lyme disease and inform public health action to reduce public vulnerability.
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    Examining Faculty and Student Perceptions of Generative AI in University Courses
    Kim, Junghwan; Klopfer, Michelle; Grohs, Jacob R.; Eldardiry, Hoda; Weichert, James; Cox, Larry A., II; Pike, Dale (Springer, 2025-01-24)
    As generative artificial intelligence (GenAI) tools such as ChatGPT become more capable and accessible, their use in educational settings is likely to grow. However, the academic community lacks a comprehensive understanding of the perceptions and attitudes of students and instructors toward these new tools. In the Fall 2023 semester, we surveyed 982 students and 76 faculty at a large public university in the United States, focusing on topics such as perceived ease of use, ethical concerns, the impact of GenAI on learning, and differences in responses by role, gender, and discipline. We found that students and faculty did not differ significantly in their attitudes toward GenAI in higher education, except regarding ease of use, hedonic motivation, habit, and interest in exploring new technologies. Students and instructors also used GenAI for coursework or teaching at similar rates, although regular use of these tools was still low across both groups. Among students, we found significant differences in attitudes between males in STEM majors and females in non-STEM majors. These findings underscore the importance of considering demographic and disciplinary diversity when developing policies and practices for integrating GenAI in educational contexts, as GenAI may influence learning outcomes differently across various groups of students. This study contributes to the broader understanding of how GenAI can be leveraged in higher education while highlighting potential areas of inequality that need to be addressed as these tools become more widely used.
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    Generative AI tools can enhance climate literacy but must be checked for biases and inaccuracies
    Atkins, Carmen; Girgente, Gina; Shirzaei, Manoochehr; Kim, Junghwan (Springer Nature, 2024-04)
    In the face of climate change, climate literacy is becoming increasingly important. With wide access to generative AI tools, such as OpenAI’s ChatGPT, we explore the potential of AI platforms for ordinary citizens asking climate literacy questions. Here, we focus on a global scale and collect responses from ChatGPT (GPT-3.5 and GPT-4) on climate change-related hazard prompts over multiple iterations by utilizing the OpenAI’s API and comparing the results with credible hazard risk indices.Wefind a general sense of agreement in comparisons and consistency in ChatGPT over the iterations. GPT-4 displayed fewer errors than GPT-3.5. Generative AI tools may be used in climate literacy, a timely topic of importance, but must be scrutinized for potential biases and inaccuracies moving forward and considered in a social context. Future work should identify and disseminate best practices for optimal use across various generative AI tools.
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    Implications for spatial non-stationarity and the neighborhood effect averaging problem (NEAP) in green inequality research: evidence from three states in the USA
    Gyanwali, Sophiya; Karki, Shashank; Jang, Kee Moon; Crawford, Thomas W.; Zhang, Mengxi; Kim, Junghwan (Springer, 2024-09-04)
    Recent studies on green space exposure have argued that overlooking human mobility could lead to erroneous exposure estimates and their associated inequality. However, these studies are limited as they focused on single cities and did not investigate multiple cities, which could exhibit variations in people’s mobility patterns and the spatial distribution of green spaces. Moreover, previous studies focused mainly on large-sized cities while overlooking other areas, such as small-sized cities and rural neighborhoods. In other words, it remains unclear the potential spatial non-stationarity issues in estimating green space exposure inequality. To fill these significant research gaps, we utilized commute data of 31,862 people from Virginia, West Virginia, and Kentucky. The deep learning technique was used to extract green spaces from street-view images to estimate people’s home-based and mobility-based green exposure levels. The results showed that the overall inequality in exposure levels reduced when people’s mobility was considered compared to the inequality based on home-based exposure levels, implying the neighborhood effect averaging problem (NEAP). Correlation coefficients between individual exposure levels and their social vulnerability indices demonstrated mixed and complex patterns regarding neighborhood type and size, demonstrating the presence of spatial non-stationarity. Our results underscore the crucial role of mobility in exposure assessments and the spatial non-stationarity issue when evaluating exposure inequalities. The results imply that local-specific studies are urgently needed to develop local policies to alleviate inequality in exposure precisely.
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    Job Accessibility as a Lens for Understanding the Urban Structure of Colonial Cities: A Digital Humanities Study of the Colonial Seoul in the 1930s Using GIS
    Kim, Youngjoon; Kim, Junghwan; Ha, Hui Jeong; Nakajima, Naoto; Lee, Jinhyung (MDPI, 2022-12-08)
    This study examined the urban structure of colonial Seoul in the 1930s, the capital city of Korea under the rule of the Japanese empire, by adopting quantitative geographical methods. We utilized a job accessibility index to operationalize the urban structure. We also used geographic information science (GIScience) analysis tools to digitize neighborhood-level sociodemographic and parcel-level business location information from historical materials. The results illustrated several findings that were not revealed by previous studies based on qualitative approaches. First, transit-based job accessibility (13.392) is significantly higher (p < 0.001) than walk-based job accessibility (10.575). Second, there is a Γ-shaped area with higher job accessibility, including the central part of colonial Seoul. Third, Japanese-dominant neighborhoods had significantly (p < 0.001) higher transit-based (27.156) job accessibility than Korean-dominant neighborhoods (9.319). Fourth, transit-based job accessibility is not significantly correlated with the unemployment rate overall. Although colonial Seoul was the seventh-largest city of the Japanese empire, few practical planning actions were taken to resolve urban issues, unlike the other large cities in mainland Japan.
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    Key Drivers of Coastal Relocation in Spatial Clusters Along the US East Coast
    Gyanwali, Sophiya (Virginia Tech, 2024-07-18)
    Coastal flooding has been increasing in frequency and severity across the US East Coast, adversely impacting the human population. Preferred adaptation strategies, such as protection and accommodation, may prove insufficient under current climate change scenarios and projected future sea level rise, prompting the coastal population to consider relocation as a more efficient disaster risk reduction strategy. This study focuses on the flood-prone urban areas along the US East Coast where residents are more willing to relocate due to coastal flooding. Using the survey data, it evaluates the flood experiences, considerations toward relocation, and preferences for relocation destinations. The extent of top concerns influencing respondents' willingness to relocate, such as crime rate, buyout programs, access to critical services and amenities, and availability of comparable housing, were further explored as indirect relocation drivers. Four study locations with heightened relocation potential were identified across urban areas on the US East Coast. Relocation drivers such as crime and limited access to services and amenities are not significantly present in these study locations. However, the absence of buyout programs and affordable housing options in similar communities leaves low-income households trapped in high-risk zones, exacerbating socioeconomic disparities, and increasing the disproportionate risk faced by marginalized populations. The findings have important implications for policymakers, urban planners, and stakeholders involved in climate adaptation and disaster risk reduction efforts. They highlight the need for targeted interventions to address socioeconomic vulnerabilities, promote equitable access to housing, and enhance the resilience of communities facing coastal hazards.
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    Multimodal Large Language Models as Built Environment Auditing Tools
    Jang, Kee Moon; Kim, Junghwan (Routledge, 2024-10-07)
    This research showcases the transformative potential of large language models (LLMs) for built environment auditing from street-view images. By empirically testing the performances of two multimodal LLMs, ChatGPT and Gemini, we confirmed that LLM-based audits strongly agree with virtual audits processed by a conventional deep learning-based method (DeepLabv3+), which has been widely adopted by existing studies on urban visual analytics. Unlike conventional field or virtual audits that require labor-intensive manual inspection or technical expertise to run computer vision algorithms, our results show that LLMs can offer an intuitive tool despite the user’s level of technical proficiency. This would allow a broader range of policy and planning stakeholders to employ LLM-based built environment auditing instruments for smart urban infrastructure management.
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    Navigating Disparities in Dental Health—A Transit-Based Investigation of Access to Dental Care in Virginia
    Kim, Junghwan; Karki, Shashank; Brickhouse, Tegwyn; Vujicic, Marko; Nasseh, Kamyar; Wang, Changzhen; Zhang, Mengxi (2024-10-30)
    Objective: To identify vulnerable areas and populations with limited access to dental care in Virginia, the study aimed (1) to calculate travel time and accessibility scores to dental care in Virginia using a transit-based accessibility model for all dental clinics and dental clinics participating in the Medicaid dental program and (2) to estimate factors associated with accessibility to dental clinics participating in the Medicaid dental program in Virginia. Methods: The study used building footprints as origins of transit trips to dental care services (or destinations). The study then computed transit-based origin–destination travel time matrices based on the detailed trip information, including in-vehicle and out-of- vehicle travel time. Accessibility scores were calculated by counting the number of dental clinics that can be reached within 60 min. Regression analysis was used to measure factors associated with accessibility scores to dental clinics participating in Medicaid. Results: Residents in smaller regions spent longer travel time to dental clinics by public transit compared with those who resided in larger regions. Medicaid participants also faced longer travel time compared with the general population. Residents spent more than three-fourths of the time waiting for public transit and walking to clinics regardless of where they live and what type of insurance they have. Associations between sociodemographic factors and accessibility scores to dental clinics participating in the Medicaid dental program varied across regions. Conclusions: Disparities in dental care accessibility exist depending on the size of regions and Medicaid participation in Virginia. The disparities in transit-based access to dental clinics and a disproportionate amount of time spent waiting for public transit and walking to dental clinics could be improved through tailored interventions taking into account the sociodemographic and geographic characteristics of each region.
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    Performance evaluation of chirp spread spectrum system and Land Mobile Satellite System by computer simulation
    Kim, Junghwan (Virginia Polytechnic Institute and State University, 1988)
    The work presented in this dissertation examines the performance of two satellite radio communication systems by computer simulation. Two simulations were separately performed for a spread spectrum chirp system as an analog communications system, and for the Land Mobile Satellite System (LMSS) channel as a digital communications system. For the simulation of analog communications, a spread spectrum system using chirp techniques called ‘Coded Multiple Chirp Spread Spectrum’ was proposed as a simple, cost-effective alternative for conventional spread spectrum systems. Its application as a spread spectrum overlay service on analog FM-TV was examined through the mutual interference analysis and spectral analysis using software programming. For the simulation of digital communications, various digital modulation schemes as well as channel encoding, block interleaving/deinterleaving, and differential encoding techniques were used for a thorough performance evaluation of a Land Mobile Satellite System under fading conditions. For this purpose, an LMSS fading channel simulator capable of simulating diverse fading characteristics for a satellite channel was designed and tested to yield various performance measures such as symbol error rate and average bit error rate.
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    Performance evaluation of nonlinear satellite link by computer simulation
    Kim, Junghwan (Virginia Polytechnic Institute and State University, 1985)
    The performance of a nonlinear satellite channel using QPSK (Quaternary Phase Shift Keying) and MSK (Minimum Shift Keying) has been studied by computer simulation. In the simulation, the pseudo randomly generated input data stream modulates the carrier and this modulated carrier passes through the typical satellite communication link, that consists of a transmit earth station, a satellite transponder, and a receiving earth station. All the signals used in the simulation procedure are real-valued and are transformed back and forth between time and frequency domains depending on the necessity by the Fast Fourier Transform (FFT) or Inverse Discrete Fourier Transform (IDFT). The simulation result represented as average Bit Error Rate (BER) gives the basis for comparison of the performance in various link conditions such as linearity, nonlinearity, band-limited and noisy channels which are expected to be encountered in practical situations.
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    Uncovering Inequalities in Food Accessibility between Koreans and Japanese in 1930s Colonial Seoul Using GIS and Open-Source Transport Analytics Tools
    Ha, Hui Jeong; Lee, Jinhyung; Kim, Junghwan; Kim, Youngjoon (MDPI, 2022-09-20)
    This study aimed to investigate the disparities and inequalities in food accessibility in colonial Seoul (Keijo [京城] in Japanese, and Gyeongseong [경성] in Korean) in the 1930s, using a geographic information system (GIS) and open-source transport analytics tools. We specifically focused on the unique social standing of people in the colonial era, namely colonial rulers (Japanese) vs. subjects (Koreans) and examined whether neighborhoods with larger proportions of colonial rulers had more access to food opportunities. For a comprehensive evaluation, we computed food accessibility by multiple transport modes (e.g., public transit and walking), as well as by different time budgets (e.g., 15 min and 30 min) and considered various sets of food options—including rice, meat, seafood, general groceries, vegetables, and fruits—when measuring and comparing accessibility across neighborhoods in colonial Seoul. We took a novel digital humanities approach by synthesizing historical materials and modern, open-source transport analysis tools to compute cumulative opportunity-based accessibility measures in 1930s colonial Seoul. The results revealed that Japanese-dominant neighborhoods had higher accessibility by both public transit and walking than Korean-dominant neighborhoods. The results further suggest that inequality and disparity in food accessibility is observed not only in contemporary society but also in the 1930s, indicating a historically rooted issue.
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    The Uneven Geography of Access to Live Performances of Western Classical Music in the United States
    Jones, Will; Kim, Junghwan (Network Design Lab - Transport Findings, 2024-11-20)
    This study evaluates accessibility to live performances of Western classical music across 3,109 U.S. counties. It analyzes 100 popular concertos and symphonies from this genre (e.g., Beethoven’s Symphony No. 9, Ode to Joy) to reveal socio-spatial disparities. Midwestern counties show poorer accessibility than West and East Coasts, with the highest mean accessibility scores in the fall and the lowest in summer. A hurdle model indicates that counties with higher population density are significantly associated with greater accessibility. An interactive online StoryMap embedded with recorded performances offers a synesthetic experience for exploring accessibility to live Western classical music performances.