• Communications of the Korean Mathematical Society
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• v.30 no.4
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• pp.385-402
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• 2015

In this paper we study the (good) semi-prime closure operations on ideals of a BCK-algebra, lower BCK-semilattice, Noetherian BCK-algebra and meet quotient ideal and then we give several theorems that make different (good) semi-prime closure operations. Moreover by given some examples we show that the given different notions are independent together, for instance there is a semi-prime closure operation, which is not a good semi-prime. Finally by given the notion of "$c_f$-Max X", we prove that every member of "$c_f$-Max X" is a prime ideal. Also we conclude some more related results.

• East Asian mathematical journal
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• v.28 no.3
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• pp.281-285
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• 2012

In this paper, the concept of *-prime ideals in non-associative near-rings is introduced and then will be studied. For this purpose, first we introduce the notions of *-operation, *-prime ideal and *-system in a near-ring. Next, we will define the *-sequence, *-strongly nilpotent *-prime radical of near-rings, and then obtain some characterizations of *-prime ideal and *-prime radical $r_s$(I) of an ideal I of near-ring N.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.2
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• pp.166-177
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• 1997

The prime mover performance of on - board Diesel Generator is well characterized by the variation of frequency and the load sharing on parallel running under electric load change. This study is aimed to configure the modeling for performance simulation regarding to DG operation which could be interested for education purpose or system analysis. The modeling had been made on the base of modules such as govenor, prime mover of diesel engine and generator with electric load system, which were then intergrated for total simula¬tion performance. One real model system has been introduced for deciding relating parameters and for the comparison of resulting performance in simulation. The responses from the modelling were confirmed in single and paralell operation, the results of which showed resonable accordance with the real system.

• Korea Journal of Hospital Management
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• v.19 no.1
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• pp.32-42
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• 2014

It is necessary to calculate prime cost of medical services accurately in order to evaluate the adequacy of medical fee. This paper aims to identify cost analysts' perception on prime cost of medical services and needs in establishing a cost accounting system in hospitals, proposing future directions and guidelines for the calculation of medical fee. A self-administered questionnaire and telephone survey on operation of a hospital cost-accounting system was conducted in November, 2012, among cost analysts currently working in the hospitals and hospital administrators planning to implement the hospital cost-accounting system. Our study shows that most of the cost analysts were aware of the importance of calculating prime cost and responded that collection of the prime cost data from government is necessary although they are less likely to provide the data in the future concerning the risk of data misuse and data security. They also responded that lack of budget allocation and excessive workload were the main reasons for not estimating the prime cost and operating cost management information system. Results show that hospital cost analysts considered the data accuracy is the most critical factor in calculating prime costs of medical services. However, there was no investment budget allocated in some hospitals or limited to less than 100 million, indicating that hospitals are reluctant to invest on implementing the cost accounting system. Respondents stated the organization that collects the prime cost of medical services among hospitals should display strong analytical capabilities, ensure data security, and maintain independence, which is most demanded. There are 57 hospitals that calculated the prime cost of medical services for 2012 by each medical department and 20 hospitals that calculated the prime cost by fee-for-services, aiming to establish a cost accounting system. Our results indicate that hospitals should voluntarily provide the accurate prime cost for medical services in order to properly evaluate the adequacy of medical fee. Consequently, it is critical to establish an independent organization to collect and appraise the data. It is also recommended that government should implement various policies to encourage hospitals to participate in the data collection to achieve the data accuracy and representativeness.

• East Asian mathematical journal
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• v.27 no.1
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• pp.75-82
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• 2011

In this paper, we will introduce the concept of fuzzy mulitplication module. We will define a new operation called a product on th family of all fuzzy submodules of a fuzzy mulitplication module. We will define a fuzzy subset of the idealization ring R+M and find some relations with the product of fuzzy submodules and product of fuzzy ideals of the idealization ring R+M. Some properties of weakly fuzzy prime submoduels and fuzzy prime submodules which are de ned by T.K.Mukherjee M.K.Sen and D.Roy will be introduced. We will investigate some properties of fuzzy prime submodules of a fuzzy multiplication module.

• Journal of the Korean Mathematical Society
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• v.60 no.2
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• pp.407-464
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• 2023

Let R be a commutative ring with identity. The structure theorem says that R is a PIR (resp., UFR, general ZPI-ring, π-ring) if and only if R is a finite direct product of PIDs (resp., UFDs, Dedekind domains, π-domains) and special primary rings. All of these four types of integral domains are Krull domains, so motivated by the structure theorem, we study the prime factorization of ideals in a ring that is a finite direct product of Krull domains and special primary rings. Such a ring will be called a general Krull ring. It is known that Krull domains can be characterized by the star operations v or t as follows: An integral domain R is a Krull domain if and only if every nonzero proper principal ideal of R can be written as a finite v- or t-product of prime ideals. However, this is not true for general Krull rings. In this paper, we introduce a new star operation u on R, so that R is a general Krull ring if and only if every proper principal ideal of R can be written as a finite u-product of prime ideals. We also study several ring-theoretic properties of general Krull rings including Kaplansky-type theorem, Mori-Nagata theorem, Nagata rings, and Noetherian property.

• Journal of the Korean Mathematical Society
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• v.54 no.6
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• pp.1699-1731
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• 2017

In this note, we define and compare some closures which behave somewhat like the radical closure. Using these closures as a starting point allows us to classify all semiprime closures on the nodal curve. Several examples provided show how these closures can differ significantly in the non-Noetherian setting.

• Korean Journal of Mathematics
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• v.17 no.1
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• pp.15-23
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• 2009

Let D be an integral domain, P be a nonzero prime ideal of D, $\{P_{\alpha}{\mid}{\alpha}{\in}{\mathcal{A}}\}$ be a nonempty set of prime ideals of D, and $\{I_{\beta}{\mid}{\beta}{\in}{\mathcal{B}}\}$ be a nonempty family of ideals of D with ${\cap}_{{\beta}{\in}{\mathcal{B}}}I_{\beta}{\neq}(0)$. Consider the following conditions: (i) If $P{\subseteq}{\cup}_{{\alpha}{\in}{\mathcal{A}}}P_{\alpha}$, then $P=P_{\alpha}$ for some ${\alpha}{\in}{\mathcal{A}}$; (ii) If ${\cap}_{{\beta}{\in}{\mathcal{B}}}I_{\beta}{\subseteq}P$, then $I_{\beta}{\subseteq}P$ for some ${\beta}{\in}{\mathcal{B}}$. In this paper, we prove that D satisfies $(i){\Leftrightarrow}D$ is a generalized weakly factorial domain of ${\dim}(D)=1{\Rightarrow}D$ satisfies $(ii){\Leftrightarrow}D$ is a weakly Krull domain of dim(D) = 1. We also study the t-operation analogs of (i) and (ii).

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.287-292
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• 2023

The U.S. National Aeronautics and Space Administration proposed a new concept of urban air mobility in the city's short-range air transport ecosystem in order to build a new low-altitude air, and the term uam is currently used worldwide. This paradigm is also being promoted by the Korean government with the goal of commercializing urban air transport services by 2025, and furthermore, the need to secure air maneuvers and transportation capacity is emerging due to the rapidly changing future operating environment and battlefield space. In other words, this study started to present the military necessity and military operation plan by introducing the 'Agility Prime' program of the US Air Force. 'Agility Prime' program was organized in order of background and concept of urban air mobility, development trend of Korean urban air mobility and analysis of the US Air Force's 'Agility Prime' program, and it is expected that this study will be followed by a follow-up study.

• Korean Journal of Construction Engineering and Management
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• v.15 no.2
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• pp.44-52
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• 2014

On March, 2013, the Government announced the Multiple Prime Contract method will be expanded in public building construction projects. The applying multiple prime contract method has been immersing issue among all stakeholders of construction project. The owner conducts the role of a general contactor as well as owner's original responsibility while construction works being executed by specialty contractors. If the owner has not experience of project management, it should be bring about increasing management cost due to the interface problems among prime contractors. With this reason, it is difficult to administrate the multiple prime contract. So far there has been no methodology of predicting management cost in the multiple prime contract. Therefore, this study aims to enable the operation of efficient multiple prime contracts by developing a model to predict their management costs.