• Journal of applied mathematics & informatics
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• 제13권1_2호
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• pp.125-138
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• 2003

Some Riccati type difference inequalities are established for the second-order nonlinear difference equations with negative neutral term $\Delta$(a(n)$\Delta$(x(n) - px(n-$\tau$))) + f(n, x($\sigma$(n))) = 0 using these inequalities we obtain some oscillation criteria for the above equation.

• 보건의료산업학회지
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• 제10권2호
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• pp.155-166
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• 2016

Objectives : This study confirmed the limitation of long-term care insurance by analyzing media contents. Methods : Articles and reviews were searched with the article searching system (KINDS) from July 2008 to December, 2015. Results : Among the 155 articles examined, 61.1% highlighted the faults of suppliers, and 25.2% indicated the responsibility of the insurer. As for their purpose, 56.8% reported on accidents, and 32.3% provided information. Furthermore, 74.2% reported on negative contents and only 25.8% on neutral contents. The negative contents consisted of requesting false insurance benefits, amending the range and price indicating the very low salaries of the care givers, limitations on the care grade assessment, and problems related with assistive devices. The majority of neutral articles is for providing information. Conclusions : There were many problems starting from the early stage of the insurance. We must pay attention to these problems. Moreover, we should try to handle and prevent these problems with supportive responses from authorities.

• 대한수학회보
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• 제45권1호
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• pp.23-31
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• 2008

In this paper, we investigate nonoscillatory solutions of a class of higher order neutral nonlinear difference equations with positive and negative coefficients $\Delta^m(x(n)+p(n)x(\tau(n)))+f_1(n,x(\sigma_1(n)))-f_2(n,x(\sigma_2(n)))=0,\;n{\geq}n_0$. Some sufficient conditions for the existence of nonoscillatory solutions are obtained.

• Journal of Korea Trade
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• 제27권1호
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• pp.60-78
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• 2023

Purpose - The study analyzed 90 online firms worldwise and observed them for ten years to investigate their investments and firm performance variabilities. This study attemped to verify the existence of agency problems in online firms. Through this, the paper intends to expand the scope of research in the fields of investment and firm value both empirically and in theory. This study also attempted to supplement the insufficient logic of previous studies by analyzing the relationship between investment and profitability. Design/methodology - In this study, the investment is subdivided into over-, under-, and neutral investments, and an empirical analysis of the firm performance was conducted. As investment generally has long-term effects, the impact of a firm's investment on future firm performance and variabilities in firm performance was considered over the short-and medium-term period. Findings - It was found that there was a negative relationship between firms with an overinvestment and future firm performance. Underinvestment has no clear statistically significant results on firm performance. This implies that overinvestment causes more reduction in future firm performance than underinvestment. It was also found that underinvestment and overinvestment significantly increased the variability of firm performance. A positive significance was found between under- and over- investment with a variability of 3 years and overinvestment with a variability of 4 years in the future. A negative relationship was found between neutral investment propensity and future performance variabilities. Neutral investment has less effect on the future performance variability of a firm than a firm's overinvestment and underinvestment. For online firms, underinvestment and overinvestment have a greater effect on the firm's future performance variability than neutral investment. Originality/value - The agency theory predicts that information asymmetry and adverse selection problems exacerbate conflicts of interest among stakeholders, thus firm performance. The study contributed to accumulating research on online firms that are currently underexplored by analyzing the investment behavior of major firms in the online industry.

• 아동학회지
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• 제36권5호
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• pp.75-94
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• 2015

This study examined short-term longitudinal reciprocal relationships between maternal parenting behavior and preschoolers' compliance/noncompliance, as well as stability in both maternal parenting behavior and preschoolers' compliance/noncompliance over time. The sample which was used for this study was taken from a two-wave (one year apart) longitudinal study of preschool-aged children and their mothers (N = 53 dyads). At both times, mothers and their children were invited to a laboratory and engaged in 25 minutes of play involving three episodes of mother-child interaction. Maternal parenting behavior and preschoolers' compliance/noncompliance during play were coded using the Dyadic Parent-Child Interaction Coding System-III (DPICS-III). Maternal codes included positive, neutral, and negative parenting behaviors and child codes were comprised of compliance and noncompliance. The results revealed that during the play session, maternal neutral and negative parenting behavior and preschoolers' compliance were stable over time. In addition, T1 maternal negative parenting behavior was significantly related to T2 child compliance/noncompliance. However, T1 child compliance/noncompliance were not significantly associated with T2 maternal parenting behavior. These findings suggest that during the preschool period, there are unidirectional effects from mothers to children.

• Communications for Statistical Applications and Methods
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• 제11권3호
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• pp.495-501
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• 2004

HJM representation of the term structure of interest rates sometimes produces the negative interest rates with positive probability. This paper shows that the condition of positive interest rates can be derived from the jump diffusion process, if a proper positive martingale process with the compensated jump process is chosen. As in Flesaker and Hughston, the condition is incorporated into the bond price process.

• 한국융합학회논문지
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• 제9권8호
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• pp.319-330
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• 2018

본 연구의 목적은 노인장기요양보험 재가보호서비스를 이용하는 노인성 치매환자 가족의 돌봄경험에 대한 평가와 가족기능과의 관계를 파악하기 위함이다. 본 연구의 대상자는 경기도 I병원 치매예방센터에서 DSM-IV기준에 의해 치매를 진단받고 노인장기요양보험 재가보호서비스를 이용하고 있는 65세 이상의 노인성 치매환자 가족구성원 121명을 대상으로 하였다. 연구결과 대상자의 평균 연령은 $53.80{\pm}10.86$세로 여성이 75.2%이었고 그 중 딸이 37.2%로 가장 많았다. 대상자의 돌봄평가는 중립적 인식의 요구감이 가장 높았고 긍정적 인식인 숙련감, 만족감이 그 다음으로 높았다. 대상자의 가족기능은 보통정도였고 영역별로 정서적 기능이 가장 높았던 반면, 의사소통이 가장 낮았다. 대상자의 돌봄평가 중 긍정적 인식의 만족감이 높고 중립적 인식의 요구감이 낮을수록 가족기능이 높았다. 추후 노인성 치매환자 가족의 돌봄에 대한 요구감을 줄이고 만족감을 향상시키며 가족의 정서적 기능과 의사소통을 증진시키기 위한 간호중재개발이 필요하다.

• ETRI Journal
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• 제46권4호
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• pp.633-647
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• 2024

In e-commerce platforms, sentiment analysis on an enormous number of user reviews efficiently enhances user satisfaction. In this article, an automated product recommendation system is developed based on machine and deep-learning models. In the initial step, the text data are acquired from the Amazon Product Reviews dataset, which includes 60 000 customer reviews with 14 806 neutral reviews, 19 567 negative reviews, and 25 627 positive reviews. Further, the text data denoising is carried out using techniques such as stop word removal, stemming, segregation, lemmatization, and tokenization. Removing stop-words (duplicate and inconsistent text) and other denoising techniques improves the classification performance and decreases the training time of the model. Next, vectorization is accomplished utilizing the term frequency-inverse document frequency technique, which converts denoised text to numerical vectors for faster code execution. The obtained feature vectors are given to the modified convolutional neural network model for sentiment analysis on e-commerce platforms. The empirical result shows that the proposed model obtained a mean accuracy of 97.40% on the APR dataset.

• 경영정보학연구
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• 제21권1호
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• pp.91-111
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• 2019

2017년 말, 전 세계적으로 비트코인을 필두로 암호화폐에 대한 투자 열풍이 시작되었으며, 특히 한국은 그 중심에 서 있는 상황이었다. 한국의 투자자들이 그간 수익성이 있는 투자 기회를 찾기가 어려웠던 만큼 새로운 투자처에 투자심리가 몰린 것으로 보인다. 하지만 암호화폐에 대한 이러한 한국의 열기는 자산의 본질적인 가치에 기초한 투자가 아니라 단기적 차익 실현 기대 및 사회적 분위기에 따른 것이기 때문에 심리적 현상에 좌우되는 바가 크다고 할 수 있다. 따라서 본 연구에서는 이를 살펴보기 위해 트위터와 비트코인을 대표로 선정하여 사람들의 소셜 감성이 암호화폐에 미치는 영향을 분석해보고자 하였다. 데이터는 2017년 11월 1일부터 2018년 4월 30일까지 총 181일간 트위터상에 노출된 비트코인 관련 게시물과 빗썸/업비트의 비트코인 가격을 대상으로 수집하였다. 수집된 트위터 데이터는 감성 분석을 통해 중립어 및 긍·부정어로 정제해주었고, 정제된 중립어, 긍정어, 부정어는 비트코인 가격에 어떤 영향을 미치는지 확인하기 위해 회귀분석 모형에 투입하였다. 회귀분석을 통해 관계를 살펴본 후에는 Granger Causality test를 통해 인과관계의 존재 여부를 확인하였다. 그 결과, 긍정어는 비트코인 가격과 정의 관계로 나타났고, 부정어는 부의 관계로 나타났다. 또한 소셜감성과 비트코인 가격간에는 양방향의 인과관계가 있음을 확인하였다. 즉, 비트코인 가격 변동이 소셜감성에 영향을 미치기도 하지만, 동시에 소셜감성의 변화도 암호화폐 투자자들의 행동에 영향을 미칠 수 있음을 확인할 수 있었다.

• Journal of Information Technology Applications and Management
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• 제26권4호
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• pp.51-69
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• 2019

One of the most considerate phenomena of the era of the Fourth Industrial Revolution is the use of digital devices. Digitalization is rapidly advancing through all areas of industry and life. Customer journey with digitalization is looking totally different from previous customer journey. The research targets were users of fashion, automobiles, cosmetics and online shopping malls. We analyzed 300 people for each valid questionnaire. The results of the study are as follows. First, it has been proven that digital experience affects positive (+) impact on purchasing intention and positive (+) impact on recommending intention and negative impact (-) on switching intent and subsequently affects positive impact (+) to purchase and incase of switching intent, negative impact (-) to purchase. Unlike traditional methods such as SPC(Service Profit Chain), the Digital experience to Purchase process Chain (DPC) has been identified to be suitable in the digital age. Second, the digital satisfied group (5 score-very satisfaction) has shown same result as above. However the digital neutral group (even though 4 score- satisfaction in five-point scale), specially in a highly competitive industry, has different from the satisfied group and 3 score-normal is same as dissatisfied group. It means that this group is that If there is a high level of attractiveness of substitute goods, there is a high possibility of switching them. It has supported Jones and Sasser [1995] that there have been two types of loyalty of true long-term loyalty and what we call false loyalty in the highly competitive industry zone which is commoditization or low differentiation, many substitutes, low cost of switching. Identifying true loyalty and false loyalty is crucial to establishing a customer experience strategy. it is necessary to actively utilize long-term digital experiences strategy to increase the total satisfaction of digital experience through all of customer purchasing journey in order to enhance the digital customer experience. It is difficult to see the effect as a one-time event. It should be scaled over the entire customer purchase process over a long period of time, which can positively affect purchase intention, recommendation intention, and conversion intention. This is also why it is difficult for second-runners to overtake first-runners in a short period.