Coalition structure generation in cooperative games with compact representations

This paper presents a new way of formalizing the coalition structure generation problem (CSG) so that we can apply constraint optimization techniques to it. Forming effective coalitions is a major research challenge in AI and multi-agent systems. CSG involves partitioning a set of agents into coalitions to maximize social surplus. Traditionally, the input of the CSG problem is a black-box function called a characteristic function, which takes a coalition as input and returns the value of the coalition. As a result, applying constraint optimization techniques to this problem has been infeasible. However, characteristic functions that appear in practice often can be represented concisely by a set of rules, rather than treating the function as a black box. Then we can solve the CSG problem more efficiently by directly applying constraint optimization techniques to this compact representation. We present new formalizations of the CSG problem by utilizing recently developed compact representation schemes for characteristic functions. We first characterize the complexity of CSG under these representation schemes. In this context, the complexity is driven more by the number of rules than by the number of agents. As an initial step toward developing efficient constraint optimization algorithms for solving the CSG problem, we also develop mixed integer programming formulations and show that an off-the-shelf optimization package can perform reasonably well

Prediction of lowest nocturnal blood glucose level based on self-monitoring of blood glucose in Japanese patients with type 2 diabetes

Available online 13 September 2018Aims: Continuous glucose monitoring (CGM) is not available for all patients with type 2 diabetes (T2D) at risk of nocturnal hypoglycemia (NH).This study was performed to predict the lowest nocturnal blood glucose (LNBG) levels. Methods: An LNBG prediction formula was developed by multivariate analysis using the data including self-monitoring of blood glucose from a formula making (FM) group of 29 insulin-treated T2D patients with CGM. The validity of the formula was assessed by nonparametric regression analysis of actual and predicted values in a formula validation group consisting of 21 other insulin-treated patients. The clinical impact on prediction was evaluated using a Parkes error grid. Results: In the FM group with a median age of 64.0, the following formula was established: Predicted LNBG (mg/dL) = 127.4-0.836 x Age (y) + 0.119 x Self-monitored fasting blood glucose (mg/dL) + 0.717 x Basal insulin dose (U/day) (standard error of calibration 17.2 mg/dL). Based on the validation results, standard error of prediction was 31.0 mg/dL All predicted values fell within zones A (no effect on clinical action) and B (little or no effect on clinical outcome) on the grid. Conclusions: LNBG could be predicted, and may be helpful for NH prevention. (C) 2018 Elsevier Inc. All rights reserved.ArticleJOURNAL OF DIABETES AND ITS COMPLICATIONS. 32(12):1118-1123 (2018)journal articl

The Novel Eryngii Method of Nipple Reduction for Female-to-Male Transsexuals

Nosaka, NobuyukiMastectomy is usually the first and most important surgical procedure in female-to-male (FTM) individuals with gender identity disorder. Nipple reduction is also important in the process of reconstructing the chest wall for a more male appearance. If the nipples remain large after a mastectomy, the results may be disappointing to many FTM transsexuals. Nipple reduction enables these individuals to go to the beach or Japanese public baths, where they may go topless in public. We therefore consider that nipple reduction is indicated for all FTM transsexuals who desire it. There are a variety of methods for the reduction of enlarged nipples for women or non-FTM patients, but only a few reports have described the process used to create masculine-appearing nipples for FTM transsexuals. We developed a novel technique called the Eryngii method for creating male-like nipples using a 4-mm diameter dermal punch knife. The name of the method refers to the Eryngii king trumpet mushroom, which the nipple resembles after the surgical process. The main strength of this method is that it permits the creation of ideal nipples without difficulty. Here we introduce the technique and discuss our history of surgical methods for nipple reduction, including improvements and elaborations

Risk Factors for Postoperative Hematoma after Chest Wall Contouring for Female-to-Male Transsexuals: A Clinical Study

Gender dysphoria is a condition in which a discrepancy between biological sex and gender identity causes distress. Many female-to-male transsexuals (FTMTS) are uncomfortable with female breasts. Chest wall contouring surgery is effective for obtaining a male-type chest, reducing mental stress, and increasing sexual satisfaction in such cases. At the Okayama University Hospital Gender Center, we have obtained positive results using an algorithm to determine the most appropriate surgical method for chest wall contouring in FTMTS patients. However, serious complications requiring reoperation, such as hematoma, may still occur. Postoperative hematomas were found in 15 (4.18%) of 358 FTMTS patients who underwent chest contouring surgery at our hospital between 2006 and 2018. Postoperative hematoma was examined retrospectively. The median time to the onset of hematoma was 7 (6-12) h after the initial surgery. The main blood vessels causing bleeding were those in the head-side skin flap region where visual confirmation was difficult and the perforator vessels from the pectoralis major muscle. Intraoperative bleeding and the operation time had a significant impact on the onset of postoperative hematoma. This is the first retrospective study that investigated the blood vessels and other factors contributing to postoperative hematoma development after chest wall contouring