• Asian-Australasian Journal of Animal Sciences
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• 제16권1호
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• pp.11-14
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• 2003

To evaluate the ewe reproductive performances of three Iranian local sheep breeds, namely Moghani, Chal and Zel, 27 rams and 473 ewes were used as the foundation flock in a crossbreeding program. The three breeds were crossed amongst themselves reciprocally. Ram breed and ewe breed showed a two-way interaction on apparent fertility. The Zel ewes showed higher fertility than the Chal and Moghani ewes (94.4 vs 77.3 and 84.6%). Prolificacy among main and individual mating groups were not significantly different (p>0.05). Zel ewes were 22.3 and 14.8% more reproductive (p<0.05) than Chal and Moghani ewes, respectively. Zel and Moghani ewes showed higher (p<0.05) ewe productivity than Chal ewes. Ram breed had a significant (p<0.05) effect on ewe efficiency. The Zel rams were not completely successful to mate with Chal ewes, this caused a to way-interaction between ram and ewe breeds. The Zel ewes mated with Chal and Moghani rams showed 26.1 and 28.5% more efficiency than those mated with Zel rams. This observation strongly supports the use of crossbreeding to improve the efficiency of the Zel ewes. With decreasing lamb mortality, through supplemented feeding of lambs in pre-weaning period, and increasing litter weight, through crossbreeding, it should be possible to improve the efficiency of Zel ewes even better than Chal and Moghani ewes. Small body size of Zel ewes that needs the lower maintenance requirements would be a well advantageous to using Zel ewes as the dam herd to produce commercial lambs in north area of Iran.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.943-946
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• 2008

Many works have been done to enable computer, as brain of robot, to learn color categorization, most of them rely on modeling of human color perception and mathematical complexities. This paper aims at developing the innate ability of the computer to learn the human-like color categorization.

• Asian-Australasian Journal of Animal Sciences
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• 제23권3호
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• pp.318-325
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• 2010

Two experiments were designed to evaluate the effects of the amino acids glycine and cysteine on cryopreservation of ram spermatozoa. After primary evaluation of collected ejaculates, the semen samples were pooled and diluted 1:4 before cooling (experiment 1) and freezing (experiment 2) with Tris-Citrate-Fructose-Yolk (TCFY) extender supplemented with different concentrations of glycine and cysteine (5, 10, 15 and 20 mM). As the control, semen was diluted and frozen in the extender without amino acids. Motility, viability and membrane integrity were assessed as the parameters for semen quality in the first experiment. In the second experiment, motility, progressive motility, viability, membranes and acrosome integrity were evaluated after the freezing-thawing process. The results of the first experiment indicated that the addition of 10 and 15 mM cysteine compared to the control (basic) extender significantly increased (p<0.01) the motility, viability and membrane integrity of spermatozoa after cooling. However, further increasing these amino acids up to 20 mM had a significant negative effect (p<0.05). Our results showed no significant differences (p>0.05) between 5 mM glycine compared to 5 mM cysteine and between 20 mM glycine and 20 mM cysteine. The results of experiment 2 showed that the amino acids significantly improved post-thaw motility, progressive motility, viability, membranes and acrosome integrity of ram spermatozoa. These positive effects were observed at concentrations between 5 to 15 mM of glycine and cysteine, with the best results at 15 mM. Further increasing of amino acid concentrations significantly decreased the post-thaw characteristics of spermatozoa, but the results showed that cysteine was better than glycine and control extenders. The data indicated that addition of glycine or cysteine to the freezing extender can be recommended for cryopreservation of ram spermatozoa. However, further studies are still needed to determine the effect of such addition on fertility in farm animals.

• Asian-Australasian Journal of Animal Sciences
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• 제17권5호
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• pp.693-699
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• 2004

Live animal selection programs that favor animals with a minimum amount of carcass fat are used for improving breeding flocks of sheep. To predict carcass characteristics of live sheep using body measurements in breeding flocks, 200 male and female lambs of two fat-tailed Iranian sheep breeds (Moghani and Makui) were used. Depth of soft tissue over the 12th rib of the live animals was measured with ultrasound (ULGR) and with hypodermic needle (NGR). The height at withers (HW), body length (BL), circumference of heart girth (CH) and width of hooks (WH), were measured. All animals were slaughtered; carcasses were cut into joints and dissected. Breed had a significant effect on all of the live easurements. The Moghani breed showed a higher value for HW, CH, ULGR and NGR, compared to that of Makui. Except for soft tissue depths; ULGR, NGR and GR, the male lambs showed higher values in live and carcass measurements than females. Percentages of carcass, total fat and intermuscular fat in females were higher than that of male lambs. In spite of the higher amount of subcutaneous and intermuscular fat in female (which is usually used for their physiological need, such as pregnancy and lactation), the male lambs had a heavier fat-tail than females. There was a wide range of variation of percentage of total carcass fat and total chemical fat content of carcass in the two breeds. Eventually this wide variation could be use by animal breeders for selection of animals with a lesser amount of carcass fat. Live weight of lambs showed a relatively low correlation with percentage of carcass lean, total fat and subcutaneous and intermuscular fat. Total lean meat was predicted with relatively high coefficients of determination in the two breeds ($R^2$=0.61 and 0.89, respectively). Live weight and carcass traits were predicted using simple measurements, but with $R^2$ ranging from 0.53 to 0.93.

• Journal of Power Electronics
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• 제13권2호
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• pp.322-328
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• 2013

This paper presents a modified Current Source Parallel Resonant Push-pull Inverter (CSPRPI) for single phase induction heating applications. One of the most important problems associated with current source parallel resonant inverters is achieving ZVS in transient intervals. This paper shows that a CSPRPI with the integral cycle control method has dynamic ZVS. According to this method, it is the Phase Locked Loop (PLL) circuit that tracks the switching frequency. The advantages of this technique are a higher efficiency, a smaller package size and a low EMI in comparison with similar topologies. Additionally, the proposed modification results in a low THD of the ac-line current. It has been measured as less than %2. To show the validity of the proposed method, a laboratory prototype is implemented with an operating frequency of 80 kHz and an output power of 400 W. The experimental results confirm the validity of the proposed single phase induction heating system.

• Journal of Power Electronics
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• 제16권1호
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• pp.173-181
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• 2016

In this paper, a new technique for harmonic optimization in cascaded H-bridge 7-level inverters is proposed. The suggested strategy is based on minimizing an objective function which simultaneously optimizes the converter utilization and Total Harmonic Distortion (THD). The Switch Utilization Ratio (SUR) is formulized for both the phase and line-line voltages of a 7-level inverter and is considered in the final objective functions. Based upon the SUR formula, utilization ratio enhancement will reduce the value of feeding DC links, which improves the efficiency and lifetime of the circuit components due to lower voltage stresses and losses. In order to achieve more effective solution in different modulation indices, it is assumed that the DC sources can be altered. Experimental validation is presented based on a three-phase 7-level inverter prototype.

• Journal of Power Electronics
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• 제12권6호
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• pp.851-858
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• 2012

This paper presents resonant inverter tuning for current source parallel resonant induction heating systems based on a new self oscillating switching technique. The phase error is suppressed in a wide range of operating frequencies in comparison with Phase Locked Loop (PLL) techniques. The proposed switching method has the capability of tuning under fast changes in the resonant frequency. According to this switching method, a multi-frequency induction heating (IH) system is proposed by using a single inverter. In comparison with multi-level inverter based IH systems, the advantages of this technique are its simple structure, better transients and wide range of operating frequencies. A laboratory prototype was built with an operating frequency of 35 kHz to 55 kHz and 300 W of output power. The performance of the IH system shows the validity of the new switching technique.

• Journal of Power Electronics
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• 제11권5호
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• pp.632-638
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• 2011

This paper presents a cascaded coil flux control based on a Current Source Parallel Resonant Push-Pull Inverter (CSPRPI) for Induction Heating (IH) applications. The most important problems associated with current source parallel resonant inverters are start-up problems and the variable response of IH systems under load variations. This paper proposes a simple cascaded control method to increase an IH system's robustness to load variations. The proposed IH has been analyzed in both the steady state and the transient state. Based on this method, the resonant frequency is tracked using Phase Locked Loop (PLL) circuits using a Multiplier Phase Detector (MPD) to achieve ZVS under the transient condition. A laboratory prototype was built with an operating frequency of 57-59 kHz and a rated power of 300 W. Simulation and experimental results verify the validity of the proposed power control method and the PLL dynamics.

• 융합경영연구
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• 제4권4호
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• pp.17-24
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• 2016

The purpose of the present study is to investigate the relationship between Management bonuses and earnings stability of the listed companies on the Tehran Stock Exchange (TSE). The population includes 94 firms selected through systematic sampling. The data is collected from the audited financial statements of the firms provided by TSE's website from 2009 to 2016. The results of multiple linear regression analysis show that there is a significant relationship between Management bonuses and earnings stability. The aim of this study primarily investigating the relationship between earnings stability and management bonus. In the case of this target, the next goal of this research is to develop a proposal for legislation in the domain of capital market, students and faculty as well as accounting information users provide research interests. Observations show many companies despite the decline in profitability, bonus managers to continually pay. Increase in listed companies Stock Exchange as well as the importance of communication between earnings quality and bonus managers in Financial Accounting the authors created an incentive to research about this relationship do. The results of this research could be the development of literature done in the past. Thus, more knowledge about the issue of sustainability and its relation to bonus managers the users of accounting information, accounting courses provide students and faculty.