PU GNN: Chargeback Fraud Detection in P2E MMORPGs via Graph Attention Networks with Imbalanced PU Labels

The recent advent of play-to-earn (P2E) systems in massively multiplayer online role-playing games (MMORPGs) has made in-game goods interchangeable with real-world values more than ever before. The goods in the P2E MMORPGs can be directly exchanged with cryptocurrencies such as Bitcoin, Ethereum, or Klaytn via blockchain networks. Unlike traditional in-game goods, once they had been written to the blockchains, P2E goods cannot be restored by the game operation teams even with chargeback fraud such as payment fraud, cancellation, or refund. To tackle the problem, we propose a novel chargeback fraud prediction method, PU GNN, which leverages graph attention networks with PU loss to capture both the players' in-game behavior with P2E token transaction patterns. With the adoption of modified GraphSMOTE, the proposed model handles the imbalanced distribution of labels in chargeback fraud datasets. The conducted experiments on three real-world P2E MMORPG datasets demonstrate that PU GNN achieves superior performances over previously suggested methods.Comment: Under Review, Industry Trac

Cooperative Spatial Retreat for Resilient Drone Networks

Drones are broadening their scope to various applications such as networking, package delivery, agriculture, rescue, and many more. For proper operation of drones, reliable communication should be guaranteed because drones are remotely controlled. When drones experience communication failure due to bad channel condition, interference, or jamming in a certain area, one existing solution is to exploit mobility or so-called spatial retreat to evacuate them from the communication failure area. However, the conventional spatial retreat scheme moves drones in random directions, which results in inefficient movement with significant evacuation time and waste of battery lifetime. In this paper, we propose a novel spatial retreat technique that takes advantage of cooperation between drones for resilient networking, which is called cooperative spatial retreat (CSR). Our performance evaluation shows that the proposed CSR significantly outperforms existing schemes. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.1

Enhancement of radiation response in human cervical cancer cells in vitro and in vivo by arsenic trioxide (As2O3)

AbstractArsenic trioxide (As2O3) inhibits cell growth and induces apoptosis in certain types of cancer cells including acute promyelocytic leukemia, prostate and ovarian carcinomas, but its effect on response of tumor cells to ionizing radiation has never been explored before. Here we demonstrate that As2O3 can sensitize human cervical cancer cells to ionizing radiation both in vitro and in vivo. As2O3 in combination with ionizing radiation have a synergistic effect in decreasing clonogenic survival and in the regression of established human cervical tumor xenografts. Pretreatment of the cells with As2O3 also synergistically enhanced radiation-induced apoptosis. Apoptosis of the cells by combined treatment of As2O3 and radiation was associated with reactive oxygen species generation and loss of mitochondrial membrane potential, resulting in the activation of caspase-9 and caspase-3. The combined treatment also resulted in an increased G2/M cell cycle distribution at the concentration of As2O3 which did not alter cell cycle when applied alone. These results indicate that As2O3 can synergistically enhance radiosensitivity of human cervix carcinoma cells in vitro and in vivo, suggesting a potential clinical applicability of combination treatment of As2O3 and ionizing radiation in cancer therapies

Optical biochemical sensor based on half-circled microdisk laser diode

In this study, a half-circled cavity based microdisk laser diode is proposed and demonstrated experimentally for an integrated photonic biochemical sensor. Conventional microdisk sensors have limitations in optical coupling and reproducibility. In order to overcome these drawbacks, we design a novel half-circled micro disk laser (HC-MDL) which is easy to manufacture and has optical output directionality. The Q-factor of the fabricated HC-MDL was measured as 7.72 × 106 using the self-heterodyne method and the side mode suppression ratio was measured as 23 dB. Moreover, gas sensing experiments were performed using the HC-MDL sensor. A wavelength shift response of 14.21 pm was obtained for 100 ppb dimethyl methylphosphonate (DMMP) gas and that of 14.70 pm was obtained for 1 ppm ethanol gas. These results indicate the possibility of highly sensitive gas detection at ppb levels using HC-MDL. This attractive feature of the HC-MDL sensor is believed to be very useful for a wide variety of optical biochemical sensor applications. © 2017 Optical Society of America.1