• Smart Structures and Systems
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• 제29권6호
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• pp.799-805
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• 2022

Permanent magnet synchronous motors (PMSMs) are widely used in systems requiring high control precision, efficiency, and reliability. Predicting the remaining useful life (RUL) with health monitoring of PMSMs prevents catastrophic failure and ensures reliable operation of system. In this study, a model-based method for predicting the RUL of PMSMs using phase current and vibration signals is proposed. The proposed method includes feature selection and RUL prediction based on a particle filter with a degradation model. The Paris-Erdogan model describing micro fatigue crack propagation is used as the degradation model. An experimental set-up to conduct accelerated life test, capable of monitoring various signals was designed in this study. Phase current and vibration data obtained from an accelerated life test of the PMSMs were used to verify the proposed approach. Features extracted from the data were clustered based on monotonicity and correlation clustering, respectively. The results identify the effectiveness of using the current data in predicting the RUL of PMSMs.

• 영어영문학
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• 제56권6호
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• pp.1135-1161
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• 2010

The interpretations of degree expressions require the postulation of new entities to represent degrees. Diverse entities such as degrees, intervals, and vectors are adopted for degree expressions. Positive degree sentences and questions are properly construed with the introduction of these entities, but their negative counterparts need more consideration. Negative degree sentences show dual patterns of entailments depending on contexts, and negative degree questions are unacceptable, making weak islands. To explicate the distinct nature of negative degree sentences and questions, Fox & Hackl (2006) provide an analysis based on degrees while Abrusan & Spector (2010) suggest a proposal in interval readings of degree expressions. I have pointed out the theoretical problems of these analyses and proposed an alternative in the framework of the vector space semantics, following Winter (2005). Bi-directional scales in vector space fit well with the dual patterns of negative degree sentences, and the notion of a reference vector is useful to accommodate the contextual influence in negative degree sentences and to deal with the unacceptability of negative degree questions.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제31권1호
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• pp.49-56
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• 2024

For a Polynomial P(z) = Σⁿ_j=0 a_jz^j with a_j ≥ a_j-1, a₀ > 0 (j = 1, 2, ..., n), a classical result of Enestrom-Kakeya says that all the zeros of P(z) lie in |z| ≤ 1. This result was generalized by A. Joyal et al. [3] where they relaxed the non-negative condition on the coefficents. This result was further generalized by Dewan and Bidkham [9] by relaxing the monotonicity of the coefficients. In this paper, we use some techniques to obtain some more generalizations of the results [3], [8], [9].

• 대한수학회보
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• 제47권4호
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• pp.675-685
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• 2010

In this paper, we consider a new class of regularized (nonconvex) generalized mixed variational inequality problems in real Hilbert space. We give the concepts of partially relaxed strongly mixed monotone and partially relaxed strongly $\theta$-pseudomonotone mappings, which are extension of the concepts given by Xia and Ding [19], Noor [13] and Kazmi et al. [9]. Further we use the auxiliary principle technique to suggest a two-step iterative algorithm for solving regularized (nonconvex) generalized mixed variational inequality problem. We prove that the convergence of the iterative algorithm requires only the continuity, partially relaxed strongly mixed monotonicity and partially relaxed strongly $\theta$-pseudomonotonicity. The theorems presented in this paper represent improvement and generalization of the previously known results for solving equilibrium problems and variational inequality problems involving the nonconvex (convex) sets, see for example Noor [13], Pang et al. [14], and Xia and Ding [19].

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권10호
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• pp.4952-4975
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• 2018

An induced hesitant linguistic aggregation operator is investigated in the paper, in which, hesitant fuzzy linguistic evaluation values are associated with probabilistic information. To deal with these hesitant fuzzy linguistic information, an induced hesitant fuzzy linguistic probabilistic ordered weighted averaging (IHFLPOWA) operator is proposed, monotonicity, boundary and idempotency of IHFLPOWA are proved. Then andness, orness and the entropy of dispersion of IHFLPOWA are analyzed, which are used to characterize the weighting vector of the operator, these properties show that IHFLPOWA is extensions of the induced linguistic ordered weighted averaging operator and linguistic probabilistic aggregation operator. In this paper, IHFLPOWA is utilized to gather linguistic information and create fuzzy ontologies, and a movie fuzzy ontology as an illustrative case study is used to show the elaboration of the proposed method and comparison with the existing linguistic aggregation operators, it seems that the IHFLPOWA operator is an useful and alternative operator for dealing with hesitant fuzzy linguistic information with probabilistic information.

• 자원ㆍ환경경제연구
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• 제19권3호
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• pp.633-658
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• 2010

본 연구에서는 1970년~2005년 기간 동안 한국 제조업의 Translog 비용함수를 분석함에 있어, 비제약 모형과 사전적으로 오목성을 부과한 제약 모형을 추정하여 그 결과를 비교하였다. 제약 모형은 비제약 모형에 비해 다소 낮은 로그우도값에 불구하고, 전 자료 구간에 대하여 정규성을 만족하여 비용함수와 생산기술 간의 쌍대성을 만족하는 추정 결과가 도출되었다. 제약 모형의 가격탄력성 분석 결과, 전력과 자본 사이에는 보완성이 존재하여 자본 수요가 증가함에 따라 전력 수요가 증가하는 것으로 나타났다. 한편 전력 수요는 노동, 연료 및 재료 수요를 모두 대체하는 방향성이 관측되어 한국 제조업이 전력 사용이 증가하는 방향으로의 구조변화를 경험하고 있는 것으로 분석되었다.

• Smart Structures and Systems
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• 제17권6호
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• pp.1067-1085
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• 2016

Nonstationary features existing in tropical storms have been frequently captured in recent field measurements, and the applicability of the stationary theory to the analysis of wind characteristics needs to be discussed. In this study, a tropical storm called Nakri measured at Taizhou Bridge site based on structural health monitoring (SHM) system in 2014 is analyzed to give a comparison of the stationary and nonstationary characteristics. The stationarity of the wind records in the view of mean and variance is first evaluated with the run test method. Then the wind data are respectively analyzed with the traditional stationary model and the wavelet-based nonstationary model. The obtained wind characteristics such as the mean wind velocity, turbulence intensity, turbulence integral scale and power spectral density (PSD) are compared accordingly. Also, the stationary and nonstationary PSDs are fitted to present the turbulence energy distribution in frequency domain, among which a modulating function is included in the nonstationary PSD to revise the non-monotonicity. The modulated nonstationary PSD can be utilized to unconditionally simulate the turbulence presented by the nonstationary wind model. The results of this study recommend a transition from stationarity to nonstationarity in the analysis of wind characteristics, and further in the accurate prediction of wind-induced vibrations for engineering structures.

• Journal of Digestive Cancer Research
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• 제7권1호
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• pp.13-17
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• 2019

Stomach cancer is the fifth most common malignancy in the world. The incidence of stomach cancer is declining worldwide, however, gastric cancer still remains the third most common cause of cancer death. The tumor, node, and metastasis (TNM) staging system has been frequently used as a method for cancer staging system and the most important reference in cancer treatment. In 2016, the classification of gastric cancer TNM staging was revised in the 8^th American Joint Committee on Cancer (AJCC) edition. There are several modifications in stomach cancer staging in this edition compared to the 7^th edition. First, the anatomical boundary between esophagus and stomach has been revised, therefore the definition of stomach cancer and esophageal cancer has refined. Second, N3 is separated into N3a and N3b in pathological classification. Patients with N3a and N3b revealed distinct prognosis in stomach cancer, and these results brought changes in pathological staging. Several large retrospective studies were conducted to compare staging between the 7^th and 8^th AJCC editions including prognostic value, stage grouping homogeneity, discriminatory ability, and monotonicity of gradients globally. The main objective of this review is to evaluate the clinical and pathological implications of AJCC 8^th staging classification in the stomach cancer.

• 전자공학회논문지C
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• 제36C권8호
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• pp.10-21
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• 1999

본 논문에서는 12비트의 해상도와 65MHz의 변환속도를 가지면서 단일 3.3V의 공급전압으로 동작하는 전류 셀 매트릭스 구조의 CMOS D/A 변환기를 제안하였다. 설계된 CMOS D/A 변환기는 우수한 단조증가성과 빠른 정착시간을 가지는 전류 셀 매트릭스 구조의 장점을 이용하면서 기존의 D/A 변환기의 전류셀 간의 문턱전압의 부정합과 접지선의 전압 강하에 의한 오차를 감소시키기 위해 트리 구조 바이어스 회로, 대칭적 접지선 연결, 캐스코드 전류 스위치를 사용하여 구현되었다. 설계된 전류 셀 매트릭스 12비트 D/A 변환기를 $0.6{\mu}m$ CMOS n-well 공정을 이용하여 제작하였다. 제작된 DAC칩을 +3.3V 단일 공급전원을 이용하여 측정한 결과, 정착시간이 20nsec로써 50MHz의 변환속도와 35.6mW의 전력소모를 나타내었다. 또한 측정된 SNR, DNL은 각각 55 dB, ${\pm}0.5LSB$,${\pm}2LSB$를 나타내었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.187-191
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• 2007

본 논문은 상위 7비트와 하위3비트의 binary-thermal decoding 방식과 segmented 전류원 구조로서 전력소모, 선형성 및 글리치 에너지등 주요 사양을 고려하여, 3.3V 10비트 CMOS D/A 변환기를 제안한다. 동적 성능을 향상 시키기위해 출력단에 return-to-zero 회로를 사용하였고, segmented 전류원 구조와 최적화 된 binary-thermal decoding 방식으로 D/A변환기가 가질 수 있는 장점은 디코딩 논리회로의 복잡성을 단순화 함으로 칩면적을 줄일 수 있다. 제안된 변환기는 $0.35{\mu}m$ CMOS n-well 표준공정을 이용한다. 설계된 회로의 상승/하강시간, 정착시간, 및 INL/DNL은 각각 1.90/2.0ns, 12.79ns, ${\pm}2.5/{\pm}0.7$ LSB로 나타난다. 또한 설계된 D/A 변환기는 3.3V의 공급전원에서는 250mW의 전력소모가 측정 된다.