Gravity model explained by the radiation model on a population landscape

Understanding the mechanisms behind human mobility patterns is crucial to improve our ability to optimize and predict traffic flows. Two representative mobility models, i.e., radiation and gravity models, have been extensively compared to each other against various empirical data sets, while their fundamental relation is far from being fully understood. In order to study such a relation, we first model the heterogeneous population landscape by generating a fractal geometry of sites and then by assigning to each site a population independently drawn from a power-law distribution. Then the radiation model on this population landscape, which we call the radiation-on-landscape (RoL) model, is compared to the gravity model to derive the distance exponent in the gravity model in terms of the properties of the population landscape, which is confirmed by the numerical simulations. Consequently, we provide a possible explanation for the origin of the distance exponent in terms of the properties of the heterogeneous population landscape, enabling us to better understand mobility patterns constrained by the travel distance.Comment: 14 pages, 4 figure

Differentiated Intrusion Detection and SVDD-based Feature Selection for Anomaly Detection

Most of existing intrusion detection techniques treat all types of attacks equally without any differentiation of the risk they pose to the information system. However, certain types of attacks are more harmful than others and their detection is critical to protection of the system. This study proposes a novel differentiated anomaly detection method that can more precisely detect intrusions of specific types of attacks. Although many researchers have been developed many efficient intrusion detection methods, fewer efforts have been made to extract effective features for host-based intrusion detection. In this study, we propose a new framework based on new viewpoints about system activities to extract host-based features, which can guide further exploration for new features. There are few feature selection methods for anomaly detections although lots of studies have been done for the feature selection both in classification and regression problems. This study proposes new support vector data description (SVDD)-based feature selection methods such as SVDD-R2-recursive feature elimination (RFE), SVDD-RFE and SVDDGradient method. Concrete experiments with both simulated and the Defense advanced research projects agency (DARPA) datasets shows promising performance of the proposed methods. These achievements in this dissertation could significantly contribute to anomaly detection field. In addition, the proposed differentiated detection and SVDD-based feature selection methods would benefit even other application areas beyond intrusion detectio

A common trajectory recapitulated by urban economies

Is there a general economic pathway recapitulated by individual cities over and over? Identifying such evolution structure, if any, would inform models for the assessment, maintenance, and forecasting of urban sustainability and economic success as a quantitative baseline. This premise seems to contradict the existing body of empirical evidences for path-dependent growth shaping the unique history of individual cities. And yet, recent empirical evidences and theoretical models have amounted to the universal patterns, mostly size-dependent, thereby expressing many of urban quantities as a set of simple scaling laws. Here, we provide a mathematical framework to integrate repeated cross-sectional data, each of which freezes in time dimension, into a frame of reference for longitudinal evolution of individual cities in time. Using data of over 100 millions employment in thousand business categories between 1998 and 2013, we decompose each city's evolution into a pre-factor and relative changes to eliminate national and global effects. In this way, we show the longitudinal dynamics of individual cities recapitulate the observed cross-sectional regularity. Larger cities are not only scaled-up versions of their smaller peers but also of their past. In addition, our model shows that both specialization and diversification are attributed to the distribution of industry's scaling exponents, resulting a critical population of 1.2 million at which a city makes an industrial transition into innovative economies

The 17 kDa band identified by multiple anti-aquaporin 2 antisera in rat kidney medulla is a histone

AbstractThe osmotic water permeability of epithelial cells of the inner medullary collecting duct of the kidney is regulated by antidiuretic hormone (ADH). ADH causes the insertion and removal of cytoplasmic vesicles containing the aquaporin (AQP-2) water channel protein which is recognized by multiple rabbit antipeptide antisera raised against amino acid sequences comprising its cytoplasmic carboxyl terminal. Immunoblots of rat kidney membrane fractions as well as human urine have all shown that AQP-2 is expressed exclusively by collecting duct cells and have identified a 29 kDa band (corresponding to the nonglycosylated AQP-2 protein), a broad 35–45 kDa band (corresponding to the mature glycosylated form of AQP-2 protein) and an additional immunoreactive 17 kDa band of unknown origin. We now report that the 17 kDa band identified by these anti-AQP-2 antisera is not an AQP-2 component but rather a denatured histone protein type H2A1. This binding of anti-AQP-2 antisera to denatured H2A1 present in protein samples derived from both kidney inner medulla and human urine is blocked specifically by preincubation of immunoblots with solutions containing the acidic protein gelatin

Removal of 10-nm contaminant particles from Si wafers using CO2 bullet particles

Removal of nanometer-sized contaminant particles (CPs) from substrates is essential in successful fabrication of nanoscale devices. The particle beam technique that uses nanometer-sized bullet particles (BPs) moving at supersonic velocity was improved by operating it at room temperature to achieve higher velocity and size uniformity of BPs and was successfully used to remove CPs as small as 10 nm. CO2 BPs were generated by gas-phase nucleation and growth in a supersonic nozzle; appropriate size and velocity of the BPs were obtained by optimizing the nozzle contours and CO2/He mixture fraction. Cleaning efficiency greater than 95% was attained. BP velocity was the most important parameter affecting removal of CPs in the 10-nm size range. Compared to cryogenic Ar or N2 particles, CO2 BPs were more uniform in size and had higher velocity and, therefore, cleaned CPs more effectively

Virtue Rules: The Evolution of the Virtue of State in East Asian International Orders

My dissertation argues the virtue of state is a crucial form of the state’s power and, at the same time, constitutes the international order. The virtue of state confers power upon the state by making it a leader in cultivating collective attunement among the states. Simultaneously, it constitutes an order among the states by making them finely attuned to various social and natural forces, including the other states. It is particularly advantageous for weak states in a hegemonic international order as they can cultivate virtue even without extensive material power resources. The state cultivates its virtue through the dialectic of performance and evaluation among what I call the evaluative community. For the state to be able to cultivate its virtue reflexively, it needs fictional moral personhood. The moral fiction of state appeared separately in Warring States China and in early modern Europe before the two separate traditions merged in 19th-century East Asia. Three major fictions of monadic, sovereign, and liberal state defined the virtues of state in East Asian international orders and provided the ethical motivation for cultivating them. I substantiate my argument by investigating the virtues of state defined by these three fictions. First, I analyze the virtue of the early modern East Asian states with its evaluative community of the shi and the monadic fiction. They used the rites and literary texts to incorporate the rhythms of imperial politics within the emotional calibration of their rulers and elites. Second, I trace how the international lawyers and East Asian scholars translated the legal conception of sovereignty into a state’s virtue in 19th-century East Asia. They cultivated sovereignty as a virtue to cope with the imperialist expansion. Third, I reconceptualize liberal internationalism as a state fiction, which has enabled the South Korean public and liberal internationalist networks to cultivate the liberal virtue. The theoretical and historical investigations of this dissertation offer an alternative conception of the state’s agency. Instead of the inefficacious pursuit of sovereignty, the virtue of state offers a flexible range of agencies that can suit each state’s material and normative conditions

Measuring national capability over big science's multidisciplinarity: A case study of nuclear fusion research

In the era of big science, countries allocate big research and development budgets to large scientific facilities that boost collaboration and research capability. A nuclear fusion device called the "tokamak" is a source of great interest for many countries because it ideally generates sustainable energy expected to solve the energy crisis in the future. Here, to explore the scientific effects of tokamaks, we map a country's research capability in nuclear fusion research with normalized revealed comparative advantage on five topical clusters-material, plasma, device, diagnostics, and simulation-detected through a dynamic topic model. Our approach captures not only the growth of China, India, and the Republic of Korea but also the decline of Canada, Japan, Sweden, and the Netherlands. Time points of their rise and fall are related to tokamak operation, highlighting the importance of large facilities in big science. The gravity model points out that two countries collaborate less in device, diagnostics, and plasma research if they have comparative advantages in different topics. This relation is a unique feature of nuclear fusion compared to other science fields. Our results can be used and extended when building national policies for big science.11Yscopu

Impossible by Conventional Means: Ten Years on from the DARPA Red Balloon Challenge

Ten years ago, DARPA launched the 'Network Challenge', more commonly known as the 'DARPA Red Balloon Challenge'. Ten red weather balloons were fixed at unknown locations in the US. An open challenge was launched to locate all ten, the first to do so would be declared the winner receiving a cash prize. A team from MIT Media Lab was able to locate them all within 9 hours using social media and a novel reward scheme that rewarded viral recruitment. This achievement was rightly seen as proof of the remarkable ability of social media, then relatively nascent, to solve real world problems such as large-scale spatial search. Upon reflection, however, the challenge was also remarkable as it succeeded despite many efforts to provide false information on the location of the balloons. At the time the false reports were filtered based on manual inspection of visual proof and comparing the IP addresses of those reporting with the purported coordinates of the balloons. In the ten years since, misinformation on social media has grown in prevalence and sophistication to be one of the defining social issues of our time. Seen differently we can cast the misinformation observed in the Red Balloon Challenge, and unexpected adverse effects in other social mobilisation challenges subsequently, not as bugs but as essential features. We further investigate the role of the increasing levels of political polarisation in modulating social mobilisation. We confirm that polarisation not only impedes the overall success of mobilisation, but also leads to a low reachability to oppositely polarised states, significantly hampering recruitment. We find that diversifying geographic pathways of social influence are key to circumvent barriers of political mobilisation and can boost the success of new open challenges