• 제어로봇시스템학회:학술대회논문집
• /
• 1998.10a
• /
• pp.445-450
• /
• 1998

In this paper, a robust nonlinear prediction-type controller (RNPC) is developed for the continuous time nonlinear system whose control objective is composed of system output and its desired value. The basic control law of RNPC is derived such that the future response of the system is first predicted by appropriate functional expansions and the control law minimizing the difference between the predicted and desired responses is then calculated. RNPC which involves two controls, i.e., the auxiliary and robust controls into the basic control, shows the stable closed loop dynamics of nonlinear system of any relative degree and provides the robustness to the nonlinear system with parameter/modeling uncertainty. Simulation tests for the position control of a two-link rigid body manipulator confirm the performance improvement and the robustness of RNPC.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.45 no.2
• /
• pp.273-282
• /
• 1996

This work is conceded with the estimation of output derivatives and their use for the design of robust controller for linear systems with system uncertainties due to modeling errors and disturbances. It is assumed that a nominal transfer function model and quantitative bounds for system uncertainties and known. The developed control schemes are shown to achieve regulation of the system output and ensures boundedness of the system states without imposing any structural conditions on system uncertainties and disturbances. Output derivative estimation is first conducted through restructuring of the plant in a specific parameterization. They are utilized for constructing robust nonlinear high-gain feedback controller of a SMC(Sliding Mode Control)type. The performances of the developed controller are evaluated and shown to be effective and useful through simulation study.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.8
• /
• pp.3759-3762
• /
• 2016

Background: Breast cancer risk assessment is a helpful method for estimating development of breast cancer at the population level. Materials and Methods: In this cross-sectional study, participants consisted of a group of 3,847 volunteers ($mean{\pm}SD$ age: $463{\pm}7.59$ years) in a convenience sample of women referred to health centers affiliated to Tehran University of Medical Sciences in Tehran, Iran. The risk of breast cancer was estimated by applying the National Cancer Institute's online version of the Gail Risk Assessment Tool. Results: Some 24.9% of women reported having one first-degree female relative with breast cancer, with 8.05% of them having two or more first-degree relatives with breast cancer. The mean five-year risk of breast cancer for all participants was $1.61{\pm}0.73%$, and 9.36% of them had a five-year risk of breast cancer >1.66%. The mean lifetime risk of breast cancer was $11.7{\pm}3.91%$. Conclusions: The Gail model is useful for assessing probability of breast cancer in Iranian women. Based on the their breast cancer risk, women may decide to accept further screening services.

• Wind and Structures
• /
• v.6 no.6
• /
• pp.451-470
• /
• 2003

The classical two-degree-of-freedom (2-d-o-f) "sectional model" is of common use to study the dynamics of suspension bridges. It takes into account the first pair of vertical and torsional modes of the bridge and describes well global oscillations caused by wind actions on the deck, yielding very useful information on the overall behaviour and the aerodynamic and aeroelastic response; however, it does not consider relative oscillations between main cables and deck. On the contrary, the 4-d-o-f model described in the two Parts of this paper includes longitudinal deformability of the hangers (assumed linear elastic in tension and unable to react in compression) and thus allows to take into account not only global oscillations, but also relative oscillations between main cables and deck. In particular, when the hangers go slack, large nonlinear oscillations are possible; if the hangers remain taut, the oscillations remain small and essentially linear: the latter behaviour has been the specific object of Part I (Sepe and Augusti 2001), while the present Part II investigates the nonlinear behaviour (coexisting large and/or small amplitude oscillations) under harmonic actions on the cables and/or on the deck, such as might be generated by vortex shedding. Because of the discontinuities and strong nonlinearity of the governing equations, the response has been investigated numerically. The results obtained for sample values of mechanical and forcing parameters seems to confirm that relative oscillations cannot a priori be excluded for very long span bridges under wind-induced loads, and they can stimulate a discussion on the actual possibility of such phenomena.

• Knowledge Management Research
• /
• v.22 no.2
• /
• pp.289-300
• /
• 2021

Proptech, which has applied information technology to the real estate market, is leading real estate transaction innovation by presenting various value creation models. This study categorizes and understands values that are created and shared in proptech-based businesses, and develops evaluation data that reflects the relative importance of individual value areas. To this end, the dimension of value creation of proptech was hierarchically constructed, and the degree of relative value creation of the sub-industries of the proptech industry was evaluated. In order to grasp the relative importance of the proposed indicators, AHP analysis was conducted for industry and academic experts. In the first stage, intangible values, relational values, and advanced values were presented. It was derived as weights between indicators through two-way comparison. This study aims to improve and develop the value-creation capability of the entire Korean proptech ecosystem in the future by evaluating the value-created competence of each sector of the proptech industry.

• The Journal of Industrial Distribution & Business
• /
• v.4 no.1
• /
• pp.15-21
• /
• 2013

Purpose - Our goal was to determine whether there is a relationship between actual profits' deviation from the profits expected in earnings per share's adjustment announcements and the degree of apparent earnings management in annual financial statements. Research design, data, and methodology - The samples consisted of 133 companies from ten industries. The companies were selected among those listed in the stock exchange, and their data were examined covering the two-year period from 2008 to 2010. Tests were conducted using a regression model and SPSS statistical software. Results - The findings indicate the following. There is no significantly positive relationship among the last earnings per share's adjustment forecast, the first earnings forecast per share, and earnings management. Moreover, the amount of the latest earnings per share's adjustment forecast relative to its first forecast is not associated with the companies' discretionary accruals items. Finally, the hypothesis that a relationship exists between companies' latest adjustments of their earnings per share and earnings management was tested the results indicate that there is no such relationship. Conclusions - The study's results suggest that the amount of earnings per share's adjustment is not a motivation for earnings management.

• Journal of Fisheries and Marine Sciences Education
• /
• v.24 no.6
• /
• pp.793-805
• /
• 2012

This study investigated the influence of mother and peer attachment on conflict resolution strategies of children. Following research questions were established. First, what is the influence of mother and peer attachment on conflict resolution strategies of children? Second, does the influence of mother and peer attachment on conflict resolution strategies of children differ according to sex? Third, what is the relative influence of mother and peer attachment on conflict resolution strategies of children? 485 fifth graders(male, 184; female, 163) from elementary schools located in Busan participated in this study and completed Inventory of Parent and Peer Attachment and Conflict Resolution Strategies Scale. Collected data were analyzed using t-test, Pearson Correlation Coefficient, Simple Regression and Multiple Regression Analysis. Major findings of this study were summarized as follows: First, both mother and peer attachment influenced on compromising and integration, avoiding and obliging strategies although the degree of influence were different. Second, the influence of mother and peer attachment on conflict resolution strategies differ according to gender. Third, the influence of peer attachment on conflict resolution strategies were greater than the one of mother attachment. Finally the significance of this study were presented with comments on limitations of this study.

• Korean Journal of Human Ecology
• /
• v.12 no.4
• /
• pp.433-447
• /
• 2003

Since self-efficacy was suggested by Bandura(1977) as the most important factor that affects human behavior, preceding studies about self-efficacy are frequently related with children, and it is a main stream that only personal factors are chosen as related factors of these studies. Considering we don't have enough studies about family factors that reflect qualitative and relational factors of adolescents' home background, this study was aimed to seize the actual condition of self-efficacy meaning perceived and emotional faith about their own ability. These are our major concerns: 1. What kind of tendency does self-efficacy and appearance stress of adolescents, family functioning show? 2. How strong are relative influences of variables on self-efficacy of adolescents? This study was operated on July and August, 2002, aimed 378 middle school and high school students in Jeon-Nam, Mokpo area. 378 question sheets were used for analysis. Followings are results of this study. First, aimed students' average mark of self-efficacy was 2.09, which meant a normal level. And in low-ranked part, self-control-efficacy was the highest, and confidence task difficulty preference was following. Furthermore, whole self-efficacy showed a little difference from the demographic factor of adolescents. In low-ranked part, however, confidence and self-efficacy showed a somewhat difference. As students grew up, confidence decreased, and male students showed higher self-control-efficacy than female ones. Second, appearance stress and family functioning degree had a strong relation with self-efficacy. Family functioning, had important interrelation not only with whole self-efficacy but also with low-ranked part of self-efficacy. In low-ranked part, self-control-efficacy and task difficulty preference were proportional to the family functioning degree. From these results, we can find that the appearance stress was an actual factor that affected the self-efficacy of adolescents, and their self-efficacy was strongly related with family functioning degree. Accordingly, affirmative emotion in family, harmonic communication among family members and sharing housekeeping works had an immediate influence on elevation of self-efficacy.

• Management & Information Systems Review
• /
• v.36 no.3
• /
• pp.17-35
• /
• 2017

This study investigates the determinants of strategic positional change. Specifically, the study suggests performance feedback affects to a firm's strategic repositioning. Performance feedback is a concept that a firm decides whether success or not by comparing its performance relative to its aspiration level. Prior studies successively discover diverse behaviors. The study suggests three unexplored relationships between performance gaps and strategic positioning. First, when a firm's performance is below relative to its aspiration level, that firm's strategic position will be deviate from the industry norm. Second, as the degree of industrial density increases, the tendency that a firm's strategic position becomes deviate from the industry norm decreases. Third, when the degree of reference group's performance decreases, the tendency that a firm's strategic position becomes deviate from the industry norm decreases. For empirical analysis, this study examines data of 538 firms that in North America crude petroleum and natural gas industry. The result reveals that the direction of a firm's strategic change is shaped when firms' performance is below relative to aspiration level. Also, this relationship is moderated as industrial density changes or when reference groups' performance decreases. This study contributes to the current literature by explaining how a firms' strategic position is decided. Also, this study reveals that reference groups' performance could affect to organizational choice.

• Korean Journal of Applied Biomechanics
• /
• v.18 no.1
• /
• pp.245-253
• /
• 2008

The purpose of this study was to analyze the effects of shoes with curved out-sole on the posture variation and its control strategy. At first, Target shoes(s) was made by evaluating the static postures of 7-female university students via 'New York State Posture Test' on shoes which made the relative angle between foot surface and ground surface of shoe change. At second, we evaluated muscle activity for 30-female university students(10 persons-3 groups) on shoes which were s(target), m shoes with curved out-sole and n shoes with flat out-sole. 1. The posture scores on New York State Posture Test were statistically different according to the relative angle changes, and the best angle for score was -7 degree but, the scores charts were like two humped camel at -2, -7degree. we made the shoe with -7 degree and curved out-sole. 2. s, m shoes with curved out-sole had graded muscle activities but, static posture on bare foot, there were the graded activity on gastrocnemius for s shoes and tibialis anterior for m shoes, but on shoes, only Gastrocnemius for s shoes.