• 공학교육연구
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• 제16권6호
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• pp.65-77
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• 2013

The purpose of this paper are to evaluate the program outcome(PO) for mechanical engineering program at Chosun University, In order to achieve the objectives of this study, we analyze the evaluation system on measuring and analyzed methods of PO. We expect that the evaluation system of PO will help program members to efficiently manage the engineering program accreditation evaluations. This paper were to improve PO evaluation system throughout assessment tools, measurements and analysis of PO between current students and faculty. This study would be confined measurements, analysis and improvement of PO for current students, and faculty in this program.

• 조명전기설비학회논문지
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• 제27권11호
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• pp.20-26
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• 2013

This paper proposes the maximum power point tracking(MPPT) control of photovoltaic system using fuzzy based variable step size perturbation & observation(FVSS-PO) method. Conventional PO and incremental conductance(IC)MPPT control algorithm generally uses fixed step size. A small fixed step size will cause the tracking speed to decrease and tracking accuracy of the MPP will decrease due to large fixed step size. Therefore, the fixed step size can't be satisfying both the tracking speed and the tracking accuracy. This paper proposes FVSS-PO MPPT algorithm that adjusts automatically step size of PO by fuzzy control according to operating conditions. The validity of MPPT algorithm proposed in this paper prove through compare with conventional PO MPPT algorithm.

• 전기학회논문지
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• 제63권12호
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• pp.1649-1654
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• 2014

This paper proposes the method which is improved a performance of PO MPPT control in PV system. The PO method is continually changed voltage toward direction that increases power, and if output power is decreased by changing voltage, a power of the conventional PO method is changed to a power before one step. These operations causes reduce of MPPT performance. Therefore, this paper proposes the MPPT method that can be improved the performance of the conventional PO method. When voltage is changed to direction of reducing power, the method proposed in this paper is changed to the voltage the opposite direction of twice step size. The MPPT performance of proposed method in this paper is compared with conventional PO method and proved the validity of this paper using these results.

• Kyungpook Mathematical Journal
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• 제54권4호
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• pp.629-638
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• 2014

The concept of prime and weakly prime ideal in semigroups has been introduced by G. Szasz [4]. In this paper, we define the involution in po-${\Gamma}$-semigroups, then we extend some results on prime, semiprime and weakly prime ideals to the involution po-${\Gamma}$-semigroup S. Also, we characterize intra-regular involution po-${\Gamma}$-semigroups. We establish that in the involution po-${\Gamma}$-semigroup S such that the involution preserves the order, an ideal of S is prime if and only if it is both weakly prime and semiprime and if S is commutative, then the prime and weakly prime ideals of S coincide. Finally, we prove that if S is a po-${\Gamma}$-semigroup with order preserving involution, then the ideals of S are prime if and only if S is intra-regular.

• 센서학회지
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• 제27권1호
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• pp.36-39
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• 2018

Transparent olivine $LiNiPO_4$ thin films on sapphire substrates were fabricated by radio frequency (RF) magnetron sputtering. The X-ray diffraction patterns show these thin films have the phase of $LiNiPO_4$ with an ordered olivine structure indexed to the orthorhombic Pmna space group. $LiNiPO_4$ thin films deposited on sapphire substrates exhibit transmittance of about 83 %. It was confirmed that the $LiNiPO_4$ thin film exhibits a high potential of 5 V-class.

• 조명전기설비학회논문지
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• 제29권12호
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• pp.40-46
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• 2015

This paper proposes the method which is improved a performance of PO MPPT control in PV system. The PO method is continually changed voltage toward direction that increases power, and if output power is decreased by changing voltage, a power of the conventional PO method is changed to a power before one step. These operations causes reduce of MPPT performance. Therefore, this paper proposes the MPPT method that can be improved the performance of the conventional PO method. When voltage is changed to direction of reducing power, the method proposed in this paper is changed to the voltage the opposite direction of twice step size. The MPPT performance of proposed method in this paper is compared with conventional PO method and proved the validity of this paper using these results.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.395-395
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• 2007

• Korean Journal of Mathematics
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• 제5권2호
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• pp.135-139
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• 1997

We introduce the concepts of weakly prime and weakly semi-prime ideals in po-${\Gamma}$-semigroup and give some characterizations of weakly prime and weakly semi-prime ideals of po-${\Gamma}$-semigroups analogous to the characterizations of weakly prime and weakly semi-prime ideals of po-semigroups considered by N. Kehayopulu.

• 대한수학회논문집
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• 제26권3호
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• pp.405-416
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• 2011

In this paper, we first introduce the concept of left strongly simple po-semigroups, then we discuss properties and characterizations nil-extensions of left strongly simple po-semigroups and semilattices of leftstrongly simple po-semigroups. Finally, we give some characterizations of the chain of left strongly simple po-semigroups.

• East Asian mathematical journal
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• 제19권2호
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• pp.233-240
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• 2003

Xie and Wu introduced an m-system in a po-semigroup. Kehayopulu gave characterizations of weakly prime ideals of po-semigroups and Lee and Kwon add two characterizations for weakly prime ideals. In this paper, we give a characterization of weakly prime ideals and a characterization of weakly semi-prime ideals in po-semigroups using m-system and n-system, respectively