Effect of foreign exchange management on firm performance using genetic algorithm and VaR

Management of foreign exchange risk is considered to be as important as trading results in firm performance when international trading and transaction of different kind of currencies are getting popular. Most previous researches on this issue have been based on the foreign exchange market and financial investing and accounting, focusing on theoretical point of view. And it is difficult to apply these research results to each company, since all companies in industry have different financial circumstances. In this paper, the solution for the foreign exchange management is proposed using GA and VaR which is very practical to export-oriented companies. The developed software enables a user to specify the criteria for the foreign exchange trading condition, constraints on dealing amount, GA operator and penalty, and variables in VaR. This approach is useful for managing foreign exchange holdings of a company in a practical way, analyzing past exchange rate trend with dealing results.     

An analysis of CH4/N2 rich biogas production, fuel treatment process and microturbine application

Biogas usually contains CH₄ and CO₂ as main components with the ratio of 6: 4, and its composition varies with wide range depending on digester conditions. In addition to concentration change of each constituent, biogas composition could be changed due to the variations in the organic matter treatment process. The aim of the study is to analyze the production and application to a microturbine system of CH₄/N₂ rich biogas produced from Gong-Ju wastewater treatment plant. CH₄/N₂ rich biogas is produced due to the internal wastewater recirculation. The internal wastewater recirculation is intended to enhance NO₃ ^? removal without additional carbon source input. As a result, the digester was shown to be the highest contributor for nitrogen removal and average CH₄ concentration was lowered compared to the typical biogas composition. Nitrate removal rate was influenced by the internal recirculation ratio. Content of N₂ has no effect on biogas clean-up system performance. Besides, adaptability of CH₄/N₂ rich biogas to microturbine was satisfactory with very low NOx and SO₂ concentration in microturbine exhaust gas. Influence of high N₂ concentration of biogas on NOx concentration was limited due to the low combustion temperature.     

Quality characteristics of imitation crab sticks made from Alaska Pollack and spent laying hen meat

Imitation crab stick (ICS) samples were divided into four treatments, a control (C) prepared with Alaska Pollack as a commercial ICS, T1, which consisted of Alaska Pollack with spent laying hen surimi collected by the pH adjust method, T2, which was composed of Alaska Pollack with spent laying hen surimi collected by the filter cake method, and T3, which consisted of Alaska Pollack with whole spent laying hen meat batter collected by the cutting method. The moisture content was significantly higher in T3 than in the other ICS samples; but, there was no significant difference in the crude protein, fat and ash content, regardless of the spent laying hen substitution methods. The lightness (L∗) and whiteness (W) was higher in the control than in the other ICS samples at 0 days of storage, whereas the yellowness (b∗) was significantly higher in T3 than in the other ICS samples. The level of polyunsaturated fatty acids was significantly higher in the control group than in the other ICS samples. Additionally, the pH increased with storage time in the spent laying hen substituted samples (T1, T2 and T3), with T1 showing a significantly higher pH during storage. The TBARS value increased with storage time in all ICS samples, with T2 showing a significantly lower TBARS value than the other ICS samples at the beginning and end of the storage periods. There was no significant difference in any sensory evaluation items among the ICS samples during storage. Thus, we assumed that T3 was better than other ICS samples, because T3 method (cutting) is much easier to collect spent laying hen surimi than T1 (pH adjust) and T2 (filter cake).     

Departure process of a single server queueing system with Markov renewal input and general service time distribution

The independence of processes in queueing systems is generally assumed when developing queueing models. However, real systems often involve several process dependencies, and failure to take these into consideration can lead to serious underestimation of the performance measures. We consider herein a single server queueing system with a Markov renewal process (MRP) for its arrival process and a general service time distribution, and derive the distribution function and correlation coefficient of the departure process. Since the departure process also often corresponds to an arrival process in downstream queues, the results obtained here can be used to derive a better approximation of the performance measures of a non-product form general queueing network.     

Adaptive History-Based Memory Schedulers for Modern Processors

Careful memory scheduling can increase memory bandwidth and overall system performance. We present a new memory scheduler that makes decisions based on the history of recently scheduled operations, providing two advantages: It can better reason about the delays associated with complex DRAM structure, and it can adapt to different observed workload.     

Quality characteristics of irradiated chicken breast rolls from broilers fed different levels of conjugated linoleic acid

Dietary conjugated linoleic acid (CLA) treatment reduced color a*- and b*-values of cooked chicken breast rolls. Sensory panels rated the color of cooked chicken rolls with CLA treatments darker than the control. The production of carbon monoxide (CO) in cooked chicken rolls increased dramatically after irradiation and was correlated with the increased redness of cooked chicken rolls after irradiation. Consumer test indicated that the color of cooked chicken rolls after irradiation was preferred to the nonirradiated, but no preference for the color among the three CLA treatments was found. Irradiation greatly increased volatile production and induced a metallic off-flavor in chicken rolls. Sensory evaluation indicated that the hardness of chicken rolls increased and juiciness decreased as the dietary level of CLA increased.     

A Time‐Constrained Information Processing Model in Ubiquitous Environments

As pervasive computing is widely adopted and reliable networks are becoming more easily accessible, there is a rapidly growing need to develop a mechanism to analyze and evaluate the performance of ubiquitous environments. This paper presents an information processing model which characterizes a ubiquitous environment where a variety of pieces of information need to be exchanged among devices within a system. The proposed model not only provides analytical tools to evaluate the performance of devices, but also makes it possible to identify key factors in designing a ubiquitous environment. For illustrative purposes, a test bed is constructed and the performance of the system is assessed based on the proposed model.     

Design of a fuel cell generation system using a PEMFC simulator

In this paper, a PCS (power conditioner system) design for a fuel cell generation system has been proposed. In order to analyze the dynamic performance of the PCS, a fuel cell stack simulator is also designed, which can consider the dynamic V–I characteristics of the PEMFC (proton exchange membrane fuel cell). First, we explain the PCS design for a fuel cell generation system in detail along with the system configuration and operational principle of the developed PEMFC simulator that has been investigated. In addition, we cover the validity of the proposed system that has been verified by informative simulation and experimental results.     

Removing escrow from ciphertext policy attribute-based encryption

Attribute-based encryption (ABE) is a promising cryptographic primitive for fine-grained access control of distributed data. In ciphertext policy attribute-based encryption (CP-ABE), each user is associated with a set of attributes and data are encrypted with access policies on attributes. A user is able to decrypt a ciphertext if and only if his attributes satisfy the access policy embedded in the ciphertext. However, key escrow is inherent in ABE systems. A curious key generation center in that construction has the power to decrypt every ciphertext. We found that most of the existing ABE schemes depending on a single key authority suffer from the key escrow problem. In this study, we propose a novel CP-ABE key issuing architecture that solves the key escrow problem. The proposed scheme separates the power of issuing user keys into two parties: the key generation center and the attribute authority. In the proposed construction, the key generation center and the attribute authority issue different parts of secret key components to users through a secure two-party computation protocol such that none of them can determine the whole set of keys of users individually. We demonstrate how the proposed key issuing protocol can be applied in the existing CP-ABE scheme and resolve the key escrow problem.     

A case study on detection and sizing of defects in steam generator tubes using eddy current testing

Eddy current testing (ECT) method is widely used to detect various types of defects occurring in nuclear steam generator tubes. Therefore, the reliability of its detection and sizing accuracy for defects should be validated. For this purpose, two tubes with defect signals were pulled from an operating steam generator and destructively examined. The defect type was a circumferential crack for one tube and an intergranular attack (IGA) for the other tube. The plus point coil probe showed a better capability to detect and size both a circumferential crack and a volumetric IGA than pancake and bobbin coil probe. The destructive results are correlated with the ECT results obtained during the in-service inspection.