Clustering electricity market participants via FRM models

Collateral mechanism in the Electricity Market ensures the payments are executed on a timely manner; thus maintains the continuous cash flow. In order to value collaterals, Takasbank, the authorized central settlement bank, creates segments of the market participants by considering their short-term and long-term debt/credit information arising from all market activities. In this study, the data regarding participants’ daily and monthly debt payment and penalty behaviors is analyzed with the aim of discovering high-risk participants that fail to clear their debts on-time frequently. Different clustering techniques along with different distance metrics are considered to obtain the best clustering. Moreover, data preprocessing techniques along with Recency, Frequency, Monetary Value (RFM) scoring have been used to determine the best representation of the data. The results show that Agglomerative Clustering with cosine distance achieves the best separated clustering when the non-normalized dataset is used; this is also acknowledged by a domain expert.

The Simulated Annealing Algorithm Based on Multi-Populations Application of TSP

Traveling salesman problem (TSP) is not only a combinatorial optimization problem but also a classical NP problem, which has has high application value. Simulated annealing algorithm is especially effective for solving TSP problems. Based on the deficiency of simulated annealing algorithm on avoiding local minima, this paper has improved the traditional simulated annealing algorithm, proposed simulated annealing algorithm of multiple populations to solve the classical TSP problem. This algorithm has introduced collateral mechanism of multiple populations and increased the initial populations so that it can include more solution set, avoid local minima, thus it has improved the optimization efficiency.This algorithm has very high use value in solving the TSP problem. Keywords: Traveling salesman problem, NP (Non-deterministic Polynomial) problem, simulated annealing algorithm, multiple populations

Experimental Study of Hemodynamics in the Circle of Willis

The Circle of Willis (CoW) is a ring like structure located at the base of brain, which is composed of a single anterior communicating artery (ACoA), paired anterior cerebral arteries (ACAs), paired internal carotid arteries (ICAs), paired posterior communicating arteries (PCoAs), paired posterior cerebral arteries (PCAs), paired vertebral arteries (VAs) and a single basilar artery (BA). It is the main cerebral blood perfusion pathway and provides an important collateral channel in patients with severe carotid or vertebral artery disease. Over 50% of stroke cases are related to the stenosis of arteries in the CoW, so the detailed information of the cerebral hemodynamics under different pathology situations is important for a variety of clinical applications. Numerous experimental studies have been performed on this field from different perspectives, include the mechanism of stenosis in the CoW [1], risk assessment of cerebral aneurysm [2] and the impact of pathological variations on the flow distribution [3]. However, none of these researches focus on the influence of ICA stenosis rates on cerebral perfusion and the specific collateral mechanism of the Circle of Willis under such situations. In this paper, an experimental study on cerebral blood perfusion and the collateral mechanism under a series of ICA stenosis rates was carried out.

Complete Disruption of Collateral Mechanism of Proximal Interphalangeal Joint of Fingers

The results are reported of a trial on the management of collateral mechanism disruption of the proximal interphalangeal joints of fingers. The incidence of the injury in Edinburgh, over a seven month period, averaged one case per week. Most (80%) had proximal avulsion of the main ligament. In the operated group all reached the state of painless stability at about two months. In the unoperated group none reached this stage, even at the final follow up, 64% complained of functional disability. It is concluded that operation is the treatment of choice for this injury.