• Journal of Information Technology Services
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• v.18 no.4
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• pp.97-113
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• 2019

With the development of sensor, communication and intelligent software technology, expectation of IoT-based service which can receive desired service automatically and anytime, anywhere is getting higher. In addition, IoT-based services have begun to anticipate the development of a hyper-connected society. Despite these expectations and anticipations, few studies have empirically identified ways to improve the intentions of prospective customers to use IoT-based services. Therefore, the purpose of this paper is to propose a theoretical model that can explain the factors that determine the intention of using IoT-based services. In addition, this study investigates what factors affect the intention to use IoT-based services focusing on the connectedness. Especially, perceived connectivity with the (virtual) community, unlike the connectivity with the machines, is newly proposed, to understand the IoT technology adoption behavior. The empirical results suggest that social relationship is one of the critical factors to affect the use of services running on interconnected technology such as IoT. When IoT-based service is recognized as a link to other communities, it has been found to have a positive effect on intention to use via perceived belongingness.

• Journal of the Ergonomics Society of Korea
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• v.33 no.5
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• pp.377-386
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• 2014

Objective: In this study, we used resting-state fMRI data to map differences in functional connectivity between a comprehensive set of 8 distinct cortical and subcortical brain regions in healthy controls and Internet addicts. We also investigated the relationship between resting state connectivity strength and the level of psychopathology (ex. score of internet addiction scale and score of Barratt impulsiveness scale). Background: There is a lot of evidence of relationship between Internet addiction and impaired inhibitory control. Clinical evidence suggests that Internet addicts have a high level of impulsivity as measured by behavioral task of response inhibition and a self report questionnaire. Method: 15 Internet addicts and 15 demographically similar non-addicts participated in the current resting-state fMRI experiment. For the connectivity analysis, regions of interests (ROIs) were defined based on the previous studies of addictions. Functional connectivity assessment for each subject was obtained by correlating time-series across the ROIs, resulting in $8{\times}8$ matrixs for each subject. Within-group, functional connectivity patterns were observed by entering the z maps of the ROIs of each subject into second-level one sample t test. Two sample t test was also performed to examine between group differences. Results: Between group, the analysis revealed that the connectivity in between the orbito frontal cortex and inferior parietal cortex, between orbito frontal cortex and putamen, between the orbito frontal cortex and anterior cingulate cortex, between the insula and anterior cingulate cortex, and between amydgala and insula was significantly stronger in control group than in the Internet addicts, while the connectivity in between the orbito frontal cortex and insula showed stronger negative correlation in the Internet addicts relative to control group (p < 0.001, uncorrected). No significant relationship between functional connectivity strength and current degree of Internet addiction and degree of impulsitivy was seen. Conclusion: This study found that Internet addicts had declined connectivity strength in the orbitofrontal cortex (OFC) and other regions (e.g., ACC, IPC, and insula) during resting-state. It may reflect deficits in the OFC function to process information from different area in the corticostriatal reward network. Application: The results might help to develop theoretical modeling of Internet addiction for Internet addiction discrimination.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.3
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• pp.1-6
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• 2016

The Internet of Things (IoT) is a new technology paradigm demanding one packaged system of various semiconductor and MEMS devices. Therefore, the development of electronic packaging technology with very high connectivity is essential for successful IoT applications. This paper discusses both fan-out wafer level packaging (FOWLP) and 3D stacking technologies to achieve the integrattion of heterogeneous devices for IoT. FOWLP has great advantages of high I/O density, high integration, and design flexibility, but ultra-fine pitch redistribution layer (RDL) and molding processes still remain as main challenges to resolve. 3D stacking is an emerging technology solving conventional packaging limits such as size, performance, cost, and scalability. Among various 3D stacking sequences wafer level via after bonding method will provide the highest connectivity with low cost. In addition substrates with ultra-thin thickness, ultra-fine pitch line/space, and low cost are required to improve system performance. The key substrate technologies are embedded trace, passive, and active substrates or ultra-thin coreless substrates.

• Anxiety and mood
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• v.10 no.2
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• pp.143-150
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• 2014

Objective : The subgenual cingulate cortex, a part of default-mode network, has been known to playa key role in the pathophysiology of depression. The previous studies have reported abnormal functional connectivity between the subgenual cingulate cortex and other brain regions in the patients with depression. The goal of this shldy was to explore the resting-state functional connectivity of the subgenual cingulate cortex between the patients with depression and healthy subjects. Methods : Twenty patients with major depression and age- and sex-matched 20 healthy subjects underwent 5-minute resting state fMRI scans. The functional connectivity map in each subject was acquired using seed-based correlation analysis with the seed located in the subgenual cingulate cortex (Talairach coordinates; x=-10, y=5, z=-10). The functional connectivity maps were calculated using AFNI and compared between the patient and healthy subject group via two-sample T-test using 3dttest++ in AFNI package. Results : Functional connectivity was decreased between the subgenual cingulate cortex and both sides of fusiform gyrus in depressed subjects. Connectivity was also decreased between the subgenual cingulate cortex and the left cerebellum in the patient group. There was no correlation between the severity of depression and the degree of functional connectivity between the subgenual cingulate cortex and the regions showing decreased functional connectivity. Conclusion : Decreased resting-state functional connectivity between the subgenual cingulate cortex and both sides of fusiform gyrus, and decreased connectivity between the subgenual cingulate cortex and the left cerebellum found in the patients with major depression in comparison to the healthy subjects might be related to abnormal emotional and cognitive processing of depressed patients.

• Investigative Magnetic Resonance Imaging
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• v.15 no.2
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• pp.110-122
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• 2011

Purpose : The purpose of this study is to establish the method generating human brain anatomical connectivity from Korean children and evaluating the network topological properties using small-world network analysis. Materials and Methods : Using diffusion tensor images (DTI) and parcellation maps of structural MRIs acquired from twelve healthy Korean children, we generated a brain structural connectivity matrix for individual. We applied one sample t-test to the connectivity maps to derive a representative anatomical connectivity for the group. By spatially normalizing the white matter bundles of participants into a template standard space, we obtained the anatomical brain network model. Network properties including clustering coefficient, characteristic path length, and global/local efficiency were also calculated. Results : We found that the structural connectivity of Korean children group preserves the small-world properties. The anatomical connectivity map obtained in this study showed that children group had higher intra-hemispheric connectivity than inter-hemispheric connectivity. We also observed that the neural connectivity of the group is high between brain stem and motorsensory areas. Conclusion : We suggested a method to examine the anatomical brain network of Korean children group. The proposed method can be used to evaluate the efficiency of anatomical brain networks in people with disease.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.1
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• pp.131-142
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• 2017

The function of urban parks as wildlife habitats is becoming increasingly important. The urban park serves as a key area for preserving urban biodiversity. The purpose of this study is to estimate the bird species diversity in 30 parks in Cheonan city and quantitatively analyze the influence of vegetation, park structure and landscape connectivity index. As the results, a total of 27 birds species and 1,509 individuals were found at the sites and the largest number of birds were found in the Cheongsa park with 17 species. The optimal regression model was selected as the explanatory variables for the logged park area (LPA), the tree cover ratio (Co_T) and the patch betweenness centrality (PB). LPA and Co_T mean the internal characteristics of the park, and PB was the external environmental variable meaning landscape connectivity. LPA was the most important factor (73.3%) as bird habitat, and the PB could be interpreted as a factor that should be considered as important (26.7%). It will be possible to consider these environmental variables in the park and green area construction and management.

• Journal of Information Technology Applications and Management
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• v.31 no.2
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• pp.51-66
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• 2024

Internet of Things (IoT) is a term that has been introduced in recent years, and it defines objects being able to connect and transfer data through the internet. Although some IoT-related products are currently available in the market, there are still some IoT problems that need to be overcome, such as the technology issues and lack of confidence and understanding of IoT. This study aims to analyze the influential factors in building successful IoT system for smart supply chain. This study develops the Analytic Hierarchy Process (AHP) to evaluate the influential factors in IoT. This study finds that tangible factors (Technology, Value and Connectivity) are more important than the intangible factors (Operation and Intelligence). Finally, this study concludes that after enterprises build a good IoT connectivity system, it is essential to combine this with good IoT technology to create a successful IoT environment. The findings may help practitioners implement IoT in smart supply chains to deal with disruptions, risks and vulnerabilities in the post-pandemic era.

• Journal of Information Technology Applications and Management
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• v.29 no.1
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• pp.1-28
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• 2022

To realize the vision of internet of things (IoT), where it is expected to bring significant impact to the global economy in the future, consideration of business models in the IoT context is necessary. This research attempts to build an enhanced artifact business model framework based on the definitions of IoT and literature on business models for analysis of IoT businesses. The framework is used to analyze four different types of players: the owner of things, vendors of devices, providers of connectivity and providers of IoT application services. The findings suggest that the owners of things tend to partner with ICT players to complement their weakness, and it tends to be connectivity providers. The device vendors leverage their strength of devices and device platforms to attract and enable 3rd party sensor/devices to interconnect, while the service providers are aiming to penetrate into customer premise. These lead to the following recommendations for non-IT players to consider in expanding into IoT business: 1) take into account differences in product development process between IT and non-IT businesses in expanding into IoT market; 2) collaborate with ICT players that acknowledge and understand the differences.

• Journal of Korea Multimedia Society
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• v.24 no.4
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• pp.583-592
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• 2021

Obsessive-compulsive disorder (OCD) is a mental disorder in which a person repeated a particular thought or feels. The domain of beliefs and guilt predicted OCD symptoms. Although there were some neuroimaging studies investigating OCD symptoms, resting-state functional magnetic resonance imaging (rs-fMRI) study investigating intra-network functional connectivity associated with guilt for OCD is not reported yet. Therefore, in the current study, we assessed the differences between intra-network functional connectivity of healthy control group and OCD group using independent component analysis (ICA) method. In addition, we also aimed to investigate the correlation between changed functional connectivity and guilt score in OCD. Total 86 participants, which consisted of 42 healthy control volunteers and 44 OCD patients, acquired rs-fMRI data using the 3T MRI. After preprocessing the fMRI data, a functional connectivity was used for group independent component analysis. The results showed that OCD patients had higher score in emotion state in beliefs and lower functional connectivity in fronto-parietal network (FPN) than control group. A decrease of functional connectivity in FPN was negatively correlated with feelings of guilt in OCD. Our results suggest excessive increase in guilt negatively affect to process emotional state and behavior or cognitive processing by influencing intrinsic brain activity.

• Journal of Korea Port Economic Association
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• v.39 no.4
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• pp.269-283
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• 2023

Based on daily data from January 4, 2016 to September 27, 2022, the impact of extreme movements of BDI on shipping companies' network connectivity was analyzed using CoVaR network connectivity. The main results and policy implications are as follows. First, according to the copula model results, the Student-t copula was selected as the most suitable model for COSCO, HMM, HRAG, MAERSK, and WAN. EVER was selected as a time-varying Gumbel copula, and YANG was selected as a time-varying rotated-Gumbel copula. Second, as a result of analysis using the TVP-VAR model, the linkage between shipping companies tended to increase when the BDI turned into an extreme risk state. In the comparison of net connectivity, the roles of COSCO and EVER changed. In addition, in the analysis of net pairwise connectivity, it was found that the change in the extreme risk state of BDI also affected the connectivity of shipping companies. In particular, EVER, WAN, and COSCO showed large changes. Taken together, the extreme fluctuations in BDI changed the role of Asian shipping companies, intensifying competition among shipping companies and strengthening risk delivery. It was confirmed that BDI has a great influence on the network connectivity of shipping companies and has an important influence on the stability of the stock market network. Therefore, the results of this study should consider not only the connectivity of shipping companies according to market conditions, but also the connectivity in extreme situations.