A new view of fuzzy ideals in \Upgamma-rings

By means of a kind of new idea, we redefine fuzzy ideals and fuzzy interior ideals in a $\Upgamma$ -ring and investigate some of their related properties. In particular, we show that the regular and semisimple $\Upgamma$ -rings can be described by using these kinds of generalized fuzzy ideals.     

Integrated framework of risk evaluation and risk allocation with bounded data

This paper presents an integrated framework for risk evaluation and risk allocation with bounded data in a critical risk management. A risk evaluation framework using the Imprecise Data Envelopment Analysis (IDEA) method is proposed to be applied to operations of Korean Army helicopters. The risks pertaining to pilots, missions and helicopters are evaluated based on bounded data, and pilots are appropriately allocated to missions and helicopters using goal programming with bounded risk scores. Using bounded data, two risk allocation models are developed to be used with the expected value and lower/upper limit values, resulting in improved reliability of the solutions. Numerical experiments show reasonable solutions and valuable information for risk management.     

Sensitivity enhancement for H2 gas detection using a SnO2–Ag2O–PdOx nanocrystalline system

Thick film H₂ sensors were fabricated using SnO₂ loaded with Ag₂O and PdO_x. The composition that gave highest sensitivity for H₂ was in the wt.% ratio of SnO₂:Ag₂O:PdO_x as 93:5:2. The nano-crystalline powders of SnO₂–Ag₂O–PdO_x composites synthesized by sol–gel method were screen printed on alumina substrates. Fabricated sensors were tested against gases like H₂, CH₄, C₃H₈, C₂H₅OH and SO₂. The composite material was found sensitive against H₂ at the working temperature 125 °C, with minor interference of other gases. H₂ gas as low as 100 ppm can be detected by the present fabricated sensors. It was found that the sensors based on SnO₂–Ag₂O–PdO_x nanocrystalline system exhibited high performance, high selectivity and very short response time to H₂ at ppm level. These characteristics make the sensor to be a promising candidate for detecting low concentrations of H₂.     

Analysis on the thermal and electrical characteristics of impregnating materials for the bifilar winding-type superconducting fault current limiter

The resistive type high temperature superconducting fault current limiter (HTSFCL) limits the fault current with the resistance that generated by fault current. The generated resistance by fault current makes large pulse power which makes the operation of HTSFCL unstable. So, the cryogenic cooling system of the resistive type HTSFCL must diffuse and eliminate the pulse energy very quickly. Although the best way is to make wide direct contact area between HTS winding and coolant as much as possible, HTS winding also need the impregnation layer which fixes and protects it from electromagnetic force. This paper deals with thermal conductivity and dielectric strength of some epoxy compounds for the impregnation of high temperature superconducting (HTS) winding at 77 K. The measured data can be used in the optimal design of impregnation for HTS winding. Aluminar filling increased the thermal conductivity of epoxy compounds. Hardener also affected the thermal conductivity and the dielectric strength of epoxy compounds.     

Electromagnetic shielding properties of soft magnetic metal and ferrite composites for application to suppress noise in a radio frequency range

Electromagnetic shielding properties of soft magnetic metal alloy (Fe-Al-Si) flakes and Ni-Zn ferrite composites for effective suppression of broadband and high frequency noise were investigated. In the soft magnetic composites, the maxima of reflection loss were shifted to high frequency with increase in content of Ni-Zn ferrite. The composites with content of 50 and 70% ferrite exhibited broadband absorptive characteristics. The broadband character- istics might be caused by the extended resonance due to an overlap between imaginary permeability and permittivity of the two composites over the frequency range from 2 to 10 GHz.     

Fuzzy Web ad selector based on Web usage mining

Internet and Web technologies are widely available, making it easier for companies to conduct business and transfer information to customers. Moreover, they speed up financial transactions efficiently, reducing the transaction costs of commercial activities that businesses would normally incur. So, Internet business has created a competitive environment, a successful company wanting to survive and gain a competitive advantage must provide an acceptable bundle of customized services that satisfy customers' needs. Despite the Internet's obvious benefits as a new communication medium its advertising gives the same advertising messages to all customers and so has suffered from poor responses. To raise a Web ad's effectiveness, we propose a Web ad selector that personalizes advertising messages for customers based on their preferences and interests. The Web ad selection system divides Web site customers with similar preferences into several segments through Web usage mining. It uses fuzzy rules that express customer segments' surfing patterns on the basis of expert advice, and recommends appropriate ads by fuzzy inference.     

The optimal determination of the space requirement and the number of transfer cranes for import containers

It is discussed how to determine the optimal amount of storage space and the optimal number of transfer cranes for import containers. A cost model is developed for the decision making. It includes the space cost, the fixed cost of transfer cranes which corresponds to the investment cost, the variable cost of transfer cranes and outside trucks which is related to the time spent for the transfer of containers. A simple solution procedure for the optimal solution is provided. The solution procedure is illustrated using a numerical example.     

Automatic control of workflow processes using ECA rules

Changes in recent business environments have created the necessity for a more efficient and effective business process management. The workflow management system is software that assists in defining business processes as well as automatically controlling the execution of the processes. We propose a new approach to the automatic execution of business processes using event-condition-action (ECA) rules that can be automatically triggered by an active database. First of all, we propose the concept of blocks that can classify process flows into several patterns. A block is a minimal unit that can specify the behaviors represented in a process model. An algorithm is developed to detect blocks from a process definition network and transform it into a hierarchical tree model. The behaviors in each block type are modeled using ACTA formalism. This provides a theoretical basis from which ECA rules are identified. The proposed ECA rule-based approach shows that it is possible to execute the workflow using the active capability of database without users' intervention. The operation of the proposed methods is illustrated through an example process.     

Improved Anaerobic Process Efficiency Using Mesophilic and Thermophilic Elutriated Phased Treatment

An innovative anaerobic digestion elutriated phased treatment (ADEPT) has been evaluated at mesophilic (M-ADEPT) (35°C) and thermophilic (T-ADEPT) (55°C) temperatures in which the organic loading rate (OLR) was increased until reactor failure (pH<5.5). Single-stage continuously stirred tank reactors (CSTRs) at both temperatures were also operated as controls (M-CSTR for 35°C and T-CSTR for 55°C). The T-CSTR failed at an OLR of 7.4 g volatile solid (VS)/L?day and the M-CSTR at an OLR of 10 g VS/L?day while the M-ADEPT continued until an OLR of 18 g VS/L?day and the T-ADEPT reached an OLR of 24 g VS/L?day before system failure. The T-CSTR produced the poorest effluent quality as manifested by high propionate concentrations (1,500–2,500 mg/L) while both M-ADEPT and T-ADEPT produced much better quality of effluent with propionate concentrations below 100 mg/L. Thus it appears that the T-ADEPT design may solve effluent quality problems associated with normally high propionate concentrations produced during thermophilic anaerobic digestion. Superior effluent quality, reduced reactor volume requirements, more stable methanogenesis due to the extended solids retention time, and uncoupling of the methanogen wasting from the refractory sludge wasting process resulted in stable and efficient processing at both temperatures for the innovative ADEPT design. Because the higher amounts of volatile fatty acids produced in the acid elutriation phase of the ADEPT system can be a favorable carbon source for biological nutrient removal in wastewater treatment plants, this positive aspect should be considered in future applications of the ADEPT system.