Probabilistic Multilevel Clustering via Composite Transportation Distance

We propose a novel probabilistic approach to multilevel clustering problems based on composite transportation distance, which is a variant of transportation distance where the underlying metric is Kullback-Leibler divergence. Our method involves solving a joint optimization problem over spaces of probability measures to simultaneously discover grouping structures within groups and among groups. By exploiting the connection of our method to the problem of finding composite transportation barycenters, we develop fast and efficient optimization algorithms even for potentially large-scale multilevel datasets. Finally, we present experimental results with both synthetic and real data to demonstrate the efficiency and scalability of the proposed approach.Comment: 25 pages, 3 figure

Gamers’ Behavior Via Avatars In Online Games

Gamers use avatars to represent themselves to interact with others in online games. However, gamers’ behavior via avatars has received insufficiently attention by electronic commerce scholars, warranting further study on this issue. Positive interactions among online gamers should foster their loyalty to the game. Therefore, this study investigated how avatar design affects gamers’ behavior via avatars. This study obtained responses from more than one thousand online gamers that were used for further analyses. Criteria were set to exclude some invalid responses, so as to increase data validity. Moreover, reliability and validity were checked by using six tests, demonstrating the adequate performance in psychometric properties. Structural equation modeling was conducted for analyses. This study found that avatar design has an important impact on gamers’ behavior via avatars. Specifically, positive perceptions on avatar design motivate the gamers to exhibit positive behavior via avatars. Findings of this study provide feasible means for electronic commerce managers to encourage gamers’ positive interactions and thus should create strong virtual communities and subsequently loyal gamers

Social Networks And Online Gamer Loyalty

Online social networks are popular issues in electronic commerce and information systems areas. However, the social network issues have received relatively little attention from scholars in online gaming contexts. Online games experience a strong growth in revenue and popularity. Therefore, this study chose to focus on social networks in online games. In online gaming studies, online gamer loyalty has been one of the recent issues. Therefore, this study consulted classic psychological theories to construct a theoretical model which contains specific hypotheses to explain how social networks impact the formulation of online gamer loyalty. This study collected the responses from more than one thousand online gamers. The demographic and gaming behavior distributions resemble those of the online gamer populations, indicating the representativeness of the study sample. This study used measurement items from the literature and slightly modified them according to the research contexts. This study used confirmatory factor analysis and various indices to verify the measurement psychometric properties, including reliability, validity, and model fit. The analytical results supported adequate psychometric properties of the measurement used in this study. Moreover, this study used the structural equation modeling technique to examine the study hypotheses. The analytical results indicated that the hypothesized aspects of social networks impact online gamer loyalty, as predicted. Furthermore, this study examined the mechanism underlying such impact. This study is the first one examining how the hypothesized aspects of social networks contribute to the development of online gamer loyalty. Findings of this study provide insights for managers of electronic business (i.e., e-business) managers to retain loyal gamers, sustain stable revenues, and build competitive advantages, demonstrating the relevance of this study to ebusiness managers

Analog of Astrophysical Magnetorotational Instability in a Couette-Taylor Flow of Polymer Fluids

We report experimental observation of an instability in a Couette-Taylor flow of a polymer fluid in a thin gap between two coaxially rotating cylinders in a regime where their angular velocity decreases with the radius while the specific angular momentum increases with the radius. In the considered regime, neither the inertial Rayleigh instability nor the purely elastic instability are possible. We propose that the observed "elasto-rotational" instability is an analog of the magnetorotational instability which plays a fundamental role in astrophysical Keplerian accretion disks.Comment: 4 pages, 1 figur

Spitzer 70 Micron Source Counts in GOODS-North

We present ultradeep Spitzer 70 μm observations of GOODS-North (Great Observatories Origins Deep Survey). For the first time, the turnover in the 70 μm Euclidean-normalized differential source counts is observed. We derive source counts down to a flux density of 1.2 mJy. From the measured source counts and fluctuation analysis, we estimate a power-law approximation of the faint 70 μm source counts of dN/dS ∝ S^−1.6, consistent with that observed for the faint 24 μm sources. An extrapolation of the 70 μm source counts to zero flux density implies a total extragalactic background light (EBL) of 7.4 ± 1.9 nW m^−2 sr^−1. The source counts above 1.2 mJy account for about 60% of the estimated EBL. From fluctuation analysis, we derive a photometric confusion level of σc = 0.30 ± 0.15 mJy (q = 5) for the Spitzer 70 μm band

Integer Vector Addition Systems with States

This paper studies reachability, coverability and inclusion problems for Integer Vector Addition Systems with States (ZVASS) and extensions and restrictions thereof. A ZVASS comprises a finite-state controller with a finite number of counters ranging over the integers. Although it is folklore that reachability in ZVASS is NP-complete, it turns out that despite their naturalness, from a complexity point of view this class has received little attention in the literature. We fill this gap by providing an in-depth analysis of the computational complexity of the aforementioned decision problems. Most interestingly, it turns out that while the addition of reset operations to ordinary VASS leads to undecidability and Ackermann-hardness of reachability and coverability, respectively, they can be added to ZVASS while retaining NP-completness of both coverability and reachability.Comment: 17 pages, 2 figure

Radio Galaxy Zoo: Knowledge Transfer Using Rotationally Invariant Self-Organising Maps

With the advent of large scale surveys the manual analysis and classification of individual radio source morphologies is rendered impossible as existing approaches do not scale. The analysis of complex morphological features in the spatial domain is a particularly important task. Here we discuss the challenges of transferring crowdsourced labels obtained from the Radio Galaxy Zoo project and introduce a proper transfer mechanism via quantile random forest regression. By using parallelized rotation and flipping invariant Kohonen-maps, image cubes of Radio Galaxy Zoo selected galaxies formed from the FIRST radio continuum and WISE infrared all sky surveys are first projected down to a two-dimensional embedding in an unsupervised way. This embedding can be seen as a discretised space of shapes with the coordinates reflecting morphological features as expressed by the automatically derived prototypes. We find that these prototypes have reconstructed physically meaningful processes across two channel images at radio and infrared wavelengths in an unsupervised manner. In the second step, images are compared with those prototypes to create a heat-map, which is the morphological fingerprint of each object and the basis for transferring the user generated labels. These heat-maps have reduced the feature space by a factor of 248 and are able to be used as the basis for subsequent ML methods. Using an ensemble of decision trees we achieve upwards of 85.7% and 80.7% accuracy when predicting the number of components and peaks in an image, respectively, using these heat-maps. We also question the currently used discrete classification schema and introduce a continuous scale that better reflects the uncertainty in transition between two classes, caused by sensitivity and resolution limits

Human Ecosystem Approach to The Dynamics of Sustainable Development in Komodo National Park, Indonesia

This article aims to present the dynamics of sustainable development in Komodo National Park (KNP) using a human ecosystem model. The Human Ecosystem model is a coherent system of biophysical and social factors capable of adaptation and sustainability over time. A rural village in Komodo island, Labuan Bajo, East Nusa Tenggara, Indonesia can be considered a human ecosystem because it has identifiable boundaries, essential ecosystem functions, resource flows, social structures, social processes (including adaptive responses to changed conditions), and dynamic continuity over a period. In 2020, the “Jurassic Park” tourism project in Komodo National Park has become a hot topic on social media after a photo of a Komodo dragon blocking a truck popped up. The project’s rejection became the most popular topic on Twitter with the hashtag #savekomodo. Various groups believe that the project will destroy the Komodo dragon’s natural habitat, evict the local population, and be carried out solely for financial gain. As a result, it is critical to understand the current situation there. The HEM helps us identify the critical resources and the social systems, as well as the key flows that contribute to the dynamic of the human ecosystem in KNP. This article yields three important findings that should be considered in the future management of KNP. First and foremost, the Komodo dragon population is still stable, but it has the potential to decline in the long term due to changes in spatial planning, an increase in tourists, a decrease in food, and poaching. Second, expanding large-capital corporations that can replace local businesses such as boat rentals, car rentals, homestay businesses, restaurants, souvenirs, and tour guides/rangers will reduce local people’s income from tourism. Third, kinship relationships between Komodo dragons and the clan of Ota Moda are eroding because of fewer encounters between Komodo dragons and the island’s indigenous tribal communities. Artikel ini bertujuan untuk menyajikan dinamika pembangunan berkelanjutan di Taman Nasional Komodo (TNK) dengan menggunakan model human ekosistem. Model human ekosistem adalah system koheren dari faktor biofisik dan sosial yang mampu beradaptasi dan berkelanjutan dari waktu ke waktu. Sebuah desa di pulau Komodo, Labuan Bajo, Nusa Tenggara Timur, Indonesia dapat dianggap sebagai human ekosistem karena memiliki batas-batas yang dapat diidentifikasi, fungsi ekosistem esensial, aliran sumber daya, struktur sosial, proses sosial (termasuk respons adaptif terhadap kondisi yang berubah), dan kontinuitas dinamis selama suatu periode. Pada tahun 2020, proyek wisata “Jurassic Park” di Taman Nasional Komodo menjadi topik hangat di media sosial setelah muncul foto Komodo yang menghalangi truk. Penolakan proyek tersebut menjadi topik paling populer di Twitter dengan tagar #savekomodo. Berbagai kalangan percaya bahwa proyek tersebut akan menghancurkan habitat alami komodo, menggusur penduduk setempat, dan dilakukan semata-mata untuk keuntungan finansial. Akibatnya, sangat penting untuk memahami situasi saat ini di sana. HEM membantu untuk mengidentifikasi sumber daya penting dan sistem sosial, serta arus utama yang berkontribusi pada dinamika human ekosistem di TNK. Artikel ini menghasilkan tiga temuan penting yang harus dipertimbangkan dalam pengelolaan TNK di masa mendatang. Pertama dan terpenting, populasi komodo masih stabil, tetapi berpotensi menurun dalam jangka panjang karena perubahan tata ruang, peningkatan wisatawan, penurunan makanan, dan perburuan liar. Kedua, ekspansi perusahaan modal besar yang dapat menggantikan usaha lokal seperti persewaan kapal, persewaan mobil, usaha homestay, restoran, cinderamata, dan pemandu wisata/ranger akan mengurangi pendapatan masyarakat lokal dari pariwisata. Ketiga, hubungan kekerabatan antara komodo dan klan Ota Moda terkikis karena lebih sedikit pertemuan antara komodo dan komunitas suku asli pulau itu

Racial and Ethnic Disparities in the Refusal of Surgical Treatment in Women 40 Years and Older With Breast Cancer in the Usa Between 2010 and 2017

PURPOSE: Although surgical resection is the main modality of treatment for breast cancer, some patients elect to refuse the recommended surgery. We assessed racial and ethnic differences in women 40 years and older who received or refused to receive surgical treatment for breast cancer in the USA and whether racial disparities in mortality were affected by their differences in the prevalence of refusal for surgical treatment. METHODS: We studied 277,127 women with breast cancer using the Surveillance, Epidemiology, and End Results (SEER) data and performed multivariable logistic regressions to investigate the association between surgery status of breast cancer and race/ethnicity. Additionally, we performed Cox regression analyses to determine the predictors of mortality outcomes. RESULTS: Of 277,127 patients with breast cancer, 1468 (0.53%) refused to receive the recommended surgical treatment in our cohort. Non-Hispanic Black women were 112% more likely to refuse the recommended surgical treatment for breast cancer compared to their non-Hispanic White counterparts [adjusted odds ratio: 2.12, 95% confidence interval (CI) 1.82-2.47]. Women who underwent breast-conserving surgery [hazards ratio (HR) 0.15, 95% CI 0.13-0.16] and mastectomy (HR 0.21, 95% CI 0.18-0.23) had lower hazard ratios of mortality as compared to women who refused the recommended treatment after adjusting for covariates. CONCLUSION: Race/ethnicity was associated with refusal for the recommended surgery, especially among non-Hispanic Black women. Also, surgery refusal was associated with a higher risk of all-cause and breast cancer-related mortality. These disparities stress the need to tailor interventions aimed at raising awareness of the importance of following physician recommendations among minorities

Diagnostic Performances of an Occupational Burnout Detection Method Designed for Healthcare Professionals.

We aimed to assess the validity (criterion and cross-cultural validity) and reliability of the first occupational burnout (OB) detection tool designed for healthcare professionals in Belgium in the context of Swiss medical practice. First, we assessed the sensitivity and specificity of the Tool. We developed this tool based on the consultation reports of 42 patients and compared its detection to the results of the Oldenburg Burnout Inventory (OLBI), filled-in by patients before a consultation. Second, we performed an inter-rater reliability (IRR) assessment on the OB symptoms and detection reached by the Tool between a psychiatrist, two psychologists, and an occupational physician. The Tool correctly identified over 80% of patients with OB, regardless of the cutoff value used for OLBI scores, reflecting its high sensitivity. Conversely, its specificity strongly varied depending on the OLBI cutoff. There was a slight to fair overall agreement between the four raters on the detection of OB and the number of OB symptoms. Around 41% of symptoms showed a substantial to an almost perfect agreement, and 36% showed a slight to a moderate agreement. The Tool seems useful for identifying OB of moderate and strong severity in both the Belgian and Swiss contexts