• 한국데이터정보과학회:학술대회논문집
• /
• 한국데이터정보과학회 2006년도 추계 학술발표회 논문집
• /
• pp.59-69
• /
• 2006

Pearson's correlation coefficient and Vector similarity are generally applied to The users' similarity weight of user based recommender system. This study is needed to find that the correlation coefficient of similarity weight is effected by the number of pair response and significance probability. From the classified correlation coefficient by the significance probability test on the correlation coefficient and pair of response, the change of MAE is studied by comparing the predicted precision of the two. The results are experimentally related with the change of MAE from the significant correlation coefficient and the number of pair response.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회B
• /
• pp.3044-3048
• /
• 2008

It is well known that Premixed Charge Compression Ignition (PCCI) diesel engines according to many technologies such a change in injection timing, multiple injection strategy, cooled EGR, intake charging and SCV have the potential to achieve homogeneous mixture in the cylinder which result in lower NOx and PM as well as performance improvements. This may generate merely the infinite number of experimental conditions. The use of Response Surface Methodology (RSM) technique can considerably pull down the number of experimental set and time demand. This paper presents the effects of both fuel injection and engine operation conditions on the combustion and emissions in the PCCI diesel engine system. The experimental results have revealed that a change in fuel injection timing and multiple injection strategy along with various operating conditions affect the combustion, emissions and BSFC characteristics in the PCCI engine.

• 대한건축학회논문집:구조계
• /
• 제35권8호
• /
• pp.149-156
• /
• 2019

In this study, dynamic responses of high - rise buildings were analyzed through the change of horizontal stiffness and yield strength among characteristics of seismic isolation system by applying middle - layer seismic isolation system to high - rise buildings of 120m height. As a result in order to prevent the displacement of the isolation layer and to control the maximum torsion angle, it is possible to appropriately control by increasing or decreasing the horizontal stiffness and the yield strength. However, depending on the maximum torsional angle and the hysteretic behavior of the seismic isolation system, excessive yield strength and horizontal stiffness increase may induce the elastic behavior of the structure and amplify the response. Therefore, it is considered that it is necessary to select the property value of the appropriate isolation device.

• 한국환경과학회지
• /
• 제7권1호
• /
• pp.27-35
• /
• 1998

The present study intends to investigate the transient response of an atmosphere /ocean general circulation model to a gradual Increase of atmospheric carbon dioxide. To detect the climatic change of the for 1% $CO_2$ run with increasing $CO_2$ and the control run with fried $CO_2$ are compared. From response of the surface air temperature due to the gradual increase of atmospheric carbon dioxide is slowly increased with latitudes and is clearly larger over continents than oceans. The annual goffal mean temperature is continuously increased with 0.03552 per one year with strong SIN ratio and distinguished from the natural variability The time dependent response of the gradual increasing $CO_2$ has the strong seasonal variability with small change In summer and large change in winter, and the strong regional In the Asian and the American continents. It has been suggested that the direct and the feedback processes in the climate systems should be investigated by the detailed sensitivity runs to get the meaninguul estimate of the $CO_2$ forced variability.

• 한국의류학회지
• /
• 제20권4호
• /
• pp.586-595
• /
• 1996

급변하는 국내외의 교역환경 변화에 따라 의류산업에도 새로운 경영 전략 수립이 요구되고 있다. Quick Response(QR)는 의류제품을 생산하는 기업의 경쟁력을 증가시키기 위해 소개된 새로운 경영 전략으로서, 유통 채녈 사이에 정보와 상품의 흐름을 효울화시켜 최대의 소비자 만족을 제공한다. 본 연구의 목적은 QR technologies의 사용현황을 밝히고 기업 특성과 QR technologies 사용수준과의 관계를 조사하였다. 종족변수는 QR technologies의 사용 수준이며, 선별된 독립변수들은 기업크기 (firm size), 기업전략 (organizational strategy), 제품종류(product category) , 패션변화(fashion change), 주기 적변화(seasonal change)였다. 조사대상은 미국 전역에서 무작위로 추출된 306개의 의류업체를 대상으로 하였으며, 1차 우편과 2차 전화로, 설문지를 통해 자료수집을 하였다. 설문 응답률은 47%(n=103)였고, 자료의 분석은 기술통계(i, e., 빈도, 퍼센트)와 비모수통계기법을 사용하였다. 가장 많이 사용되고 있는 QR technologies는 소량주문(small lot orders) , 단기 사이클 재단 계획 (short cycle cut planning)과 고객의 견이 반영 된 생산계획 (Production planning with customers)이였다. 가장 적게 사용되고 있는 QR technologies는 전자 재주문(electronic reorder)과 단위 생산 시스템 (unit production system)이 였다. QR technologies 사용수준에 관계가 있는 것은 기업크기 (firm size), 기업전략 (organizational strategy), 패션변화(fashion change) 임으로 나타났다. 의류업체의 크기가 클수록, 혁신적 선도기업 일수록, 패션변화가 큰 제품을 취급할수록 QR technologies의 사용수준이 높은 것으로 나타났다. 의류업체는 자원과 생산하는 제품종류에 따라 경영전략과 QR technologies의 사용수준이 다양하였다.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
• /
• pp.113-114
• /
• 2004

In order to classify the groundwater recharge characteristics in an urban area, a time series analysis of groundwater level data was performed. For this study, the daily groundwater level data from 35 monitoring wells were collected for 3 years (Fig. 1). The use of the cross-correlation function (CCF), one of the time series analysis, showed both the close relationship between rainfall and groundwater level change and the lag time (delay time) of groundwater level fluctuation after a rainfall event. Based on the result of CCF, monitored wells were classified into two major groups. Group I wells (n=10) showed a fast response of groundwater level change to rainfall event, with a delay time of maximum correlation between rainfall and groundwater level near 1 to 7 days. On the other hand, the delay time of 17-68 days was observed from Group II wells (n=25) (Fig. 1). The fast response in Group I wells is possibly caused by the change of hydraulic pressure of bedrock aquifer due to the rainfall recharge, rather than the direct response to rainfall recharge.

• 한국기계가공학회지
• /
• 제19권11호
• /
• pp.29-34
• /
• 2020

In this study, a sensitivity formulation was applied to analyze the dynamic response due to the effect of the excitation force for the undamped vibration of the cantilever beam. The theoretically fundamental formulations were derived considering an eigenvalue problem and its modal analysis to govern the second order algebraic differential equation in terms of the change in the modal coordinate with respect to the design parameters. A representative physical quantity pertaining to the dynamic response, that is, the rate of change in the dynamic displacement, was observed by changing the design variables, such as the cross-sectional area of the beam. The numerical results were obtained at various locations, considering the application of the external forces and observation of the dynamic displacement. When the detection position was closer to the free end of the cantilever beam, the sensitivity of the dynamic displacement was higher, as predicted through the oscillating motion of the beam. The presented findings can provide guidance to compute the dynamic sensitivity for a flexibly connected structure under dynamic excitations.

• 한국산업융합학회 논문집
• /
• 제5권1호
• /
• pp.21-26
• /
• 2002

Response time of actuator in a hydraulic system may be important and necessary to avoid failures and to improve the efficiency of operation. Flow restricting devices can result in a decrease in the peak pressure, but may change the response time. The response time has an important effect on both operator and operator perceived smoothness. The response time should correspond to how fast a system responds to a given disturbance at the system boundary, Occasionally the appropriate response time is not easily determined. This study is on the characteristics of response time in the hydraulic system.

• 한국공작기계학회논문집
• /
• 제12권1호
• /
• pp.92-100
• /
• 2003

Using a quarter car model, an analytic method for performance estimation of a vehicle suspension system with respect to frequency response, RMS response and performance index is presented. From frequency response function, compromization of response performance to the whole frequency range is verified and from RMS response and performance index, sensitivity of ride md handling characteristics are examined. Using a full car model, sweet area(stable ride area) are determined and performance sensitivity is estimated according to the change of feedback gains. In order to esimate the output sensitivity, response we is displayed using a 3-dimensional contour plot. Design data n suggested for optimal design parameter esimation, which maximize the performance of the given suspension system.

• 대한기계학회논문집B
• /
• 제26권11호
• /
• pp.1488-1495
• /
• 2002

The response time represents how fast a system responds to a given disturbance at the system boundary. Flow restricting devices for controlling transients can result in a decrease in the peakm pressure, but may change response time. Response lag in a hydraulic system leads to inefficient working cycle and operator discomfort. The experiments were conducted in order to get information on the parameters which exert appreciable influence on the response time. The experimental apparatu including a hydraulic actuator, orifice and a hydraulic pump was an idealization of a bucket hydraulic shifting system. Experimental results show that the response time depends on operating pressure and flow rate. The effects of orifice type and size on the response time are quantified.