• Title/Summary/Keyword: Performance Quantity

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Performance Analysis of Reaction Wheel according to Bearing Preload and Oil Quantity (베어링 예압 및 오일양에 따른 반작용 휠 성능 분석)

  • Kim, Jichul;Yoon, Jinhyuk;Lee, Junyong;Oh, Hwasuk
    • Journal of Aerospace System Engineering
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    • v.10 no.1
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    • pp.35-42
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    • 2016
  • Bearing friction and disturbance are the important parameters in control spacecraft using reaction wheel. In this paper, those parameters are estimated by preload and oil quantity. In order to determine the bearing preload's impact on performance, measure the disturbance and the bearing friction coefficient with increasing the preload to the allowed amount. And, find the relationship between oil quantity and bearing friction coefficient, measure it with increasing the oil amount in the bearing. With these results as a reference, find the appropriate amount of preload and oil quantity.

Early Warning System for Inventory Management using Prediction Model and EOQ Algorithm

  • Majapahit, Sali Alas;Hwang, Mintae
    • Journal of information and communication convergence engineering
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    • v.19 no.4
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    • pp.221-227
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    • 2021
  • An early warning system was developed to help identify stock status as early as possible. For performance to improve, there needs to be a feature to predict the amount of stock that must be provided and a feature to estimate when to buy goods. This research was conducted to improve the inventory early warning system and optimize the Reminder Block's performance in minimum stock settings. The models used in this study are the single exponential smoothing (SES) method for prediction and the economic order quantity (EOQ) model for determining the quantity. The research was conducted by analyzing the Reminder Block in the early warning system, identifying data needs, and implementing the SES and EOQ mathematical models into the Reminder Block. This research proposes a new Reminder Block that has been added to the SES and EOQ models. It is hoped that this study will help in obtaining accurate information about the time and quantity of repurchases for efficient inventory management.

A Study on the design of operations system for managing the mobile communication network (이동통신망 관리용 운용시스템 설계에 관한 연구)

  • 하기종
    • Journal of the Korea Society for Simulation
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    • v.6 no.2
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    • pp.71-79
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    • 1997
  • In this paper, operations system was designed for the centralization of data processing of various state information from the facilities of mobile communication network. And the system performance experimental system module was measured and analyzed from the designed experimental system module. The configuration of system design was presented with the centralized type to monite and control the facilities of mobile communication network in the central office. The communication process design of the internal system was implemented with the resource of message queue having a excellent transmission ability for processing of a great quantity of information in the inter-process communication among communication resources of UNIX system. The process with a server function from the internal communication processes was constructed with a single server or a double server according to the quantity of operations and implemented with the policy of the presented server. And then, we have measured performance elements in accordance with the change of input parameters from the designed experimental module : response time, waiting time, buffer length, the maximum quantity existing in message queue. And from these results, we have compared and analyzed the system state each server algorithm according to performance variations.

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Analysis of computational fluid dynamics on design of nozzle for integrated cryogenic gas and MQL(minimum quantity lubrication) (극저온 가스와 MQL(minimum quantity lubrication)의 복합 분사를 위한 하이브리드 노즐 설계에 관한 전산유체역학 해석)

  • Song, Ki-Hyeok;Shin, Bong-Cheol;Yoon, Gil-Sang;Ha, Seok-Jae
    • Design & Manufacturing
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    • v.13 no.3
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    • pp.41-47
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    • 2019
  • In conventional machining, the use of cutting fluid is essential to reduce cutting heat and to improve machining quality. However, to increase the performance of cutting fluids, various chemical components have been added. However, these chemical components during machining have a negative impact on the health of workers and cutting environment. In current machining, environment-friendly machining is conducted using MQL (minimum quantity lubrication) or cryogenic air spraying to minimize the harmful effects. In this study, the injection nozzle that can combined injecting minimum quantity lubrication(MQL) and cryogenic gas was designed and the shape optimization was performed by using computational fluid dynamics(CFD) and design of experiment(DOE). Performance verification was performed for the designed nozzle. The diameter of the sprayed fluid at a distance of 30 mm from the nozzle was analyzed to be 21 mm. It was also analyzed to lower the aerosol temperature to about 260~270K.

The Effect of Real-Time Individual Process Performance Feedback on Computer-based Group Idea Generation

  • Jung, J.H.
    • The Journal of Information Systems
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    • v.23 no.2
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    • pp.91-107
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    • 2014
  • In computer-mediated idea generation where contributions can be anonymous, the ability to accurately monitor performances is limited, inducing social loafing. Prior research has suggested that social loafing is likely an important factor in reducing task performance. Researchers have theorized that loafing could be minimized if clear performance feedback is provided. Our prior study evidences a substantial performance gain by the provision of real time performance information about who is contributing and who is not. However, our prior study incorporated the quantity feedback only to create a larger pool of ideas based on the long-standing assumption (i.e., quantity breeds quality), not considering the quality feedback. As a result, taking advantage of anonymity in the form of pseudonymity, individuals in almost all groups exhibited a tendency of self-presentation by capitalizing on ideas of which quality was low and even frivolous (i.e., junk comments) toward the later stages of the session. Thus, we have learned that the quantity performance feedback alone does not have enough restrictiveness to consistently control the performance behavior throughout the session. Since a process chart allows participants to monitor process variation by comparing new performance data to past performance data, we incorporated real-time visual process performance feedback to reveal performance histories by connecting the sequence of idea quality scores in a time-series format. Using this environment, a laboratory experiment was conducted with five-member groups that examined the influence of both identifiability (i.e., anonymity versus pseudonymity) and process performance feedback (i.e., yes or no) in a $2{\times}2$ factorial design. The result showed that groups in the process performance feedback treatment outperformed groups in the no feedback treatment. Additionally, process performance feedback and identifiability interacted such that groups in the process performance feedback/pseudonymity treatment had the highest performance. The implications of these findings for future research, as well as the implications for the design of group idea generation procedures are discussed.

Relative Effects of Individual and Group Feedback on the Quantity and Quality of Task Performance (개인피드백과 집단피드백이 과업 수행의 양과 질에 미치는 상대적 효과 검증)

  • Moon, Kwangsu;Cha, Minjung;Lee, Kyehoon;Oah, Shezeen
    • The Journal of the Korea Contents Association
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    • v.14 no.12
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    • pp.655-664
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    • 2014
  • Recently, many organizations are utilizing the team system. However, researches on a technique for efficient and effective feedback to improve a team performance is few. This study compared the relative effects of individual and group feedback on the quantity and quality of work performance. The task was to type English documents on a PC computer and both the number of words typed (quantity) and the percentage of correctly typed words (quality) were measured. Mixed design was adopted and 48 participants were randomly assigned to either individual or group feedback condition. Each group consisted of three participants and completed four sessions together. Under the individual feedback condition, each participant was provided with information on his/her own work performance, while under the group feedback condition, three participants were provided with information on their total work performance. Results showed that both feedback were effective to increase the quantity of performance. However, the effect size of treatment was more high under the group feedback than individual feedback. In addition, the accuracy of typed words was significantly improved only under the group feedback condition. Therefore, the group feedback was more effective and efficient than individual feedback to increase team performance. However, more studies are needed to generalize these results, especially, it is necessary to consider the cultural differences and type of task in the future studies.

Effect of Quantity of Working Fluid on Performance of a Heat Pipe (히트 파이프의 작동유체 충전량이 성능에 미치는 영향)

  • Shin, D.Y.;Ro, S.T.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.1 no.4
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    • pp.313-318
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    • 1989
  • Experiments have been performed to find an optimum filling quantity of working fluid in a heat pipe. The optimum operation has been defined to give a minimum temperature difference between evaporator and condenser. The experimental results show that there exists an optimum filling quantity which is slightly smaller than that calculated by the well known formula from the geometry of the wick. When the concaved vapor-liquid interface at the wick is taken into account to calculate the required quantity of working fluid, the computed value agrees with the experimentally determined quantity.

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Evaluation of Quantity Discounts for Buyer's Stocking Risk

  • Shin, Ho-Jung;Benton, W.C.;Park, Soo-Hoon
    • Management Science and Financial Engineering
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    • v.16 no.3
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    • pp.21-47
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    • 2010
  • Quantity discounts provide a practical foundation for supply chain inventory policies, improving the supplier's profit and reducing the buyer's inventory cost simultaneously. Traditional quantity-discount research, which deals with inventory coordination between a buyer and a supplier, is extended to a stationary stochastic environment. This research shows that the magnitude of the optimal discounts scheduled by the deterministic quantity discount models may not be large enough to cover the buyer's additional inventory stocking risks under uncertain conditions. As a result, the buyer's total inventory cost may often increase rather than decrease. In contrast, the proposed model allows the supplier to identify the discount level, which shares the buyer's amplified risk associated with temporary overstocking and ensures that both buyer and supplier benefit economically. The performance of the proposed model was tested in the continuous review environments via numerical experiments. The experimental results support the proposed method as a feasible alternative in coordinating inventory decisions under stochastic demand.

Recognition of Noise Quantity by Neural Network using Linear Predictive Coefficient (선형예측계수를 사용한 신경회로망에 의한 잡음량의 인식)

  • Choi, Jae-Seung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2008.10a
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    • pp.379-382
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    • 2008
  • In order to reduce the noise quantity in a conversation under the noisy environment, it is necessary for the signal processing system to process adaptively according to the noise quantity in order to enhance the performance. There fore this paper presents a recognition method for noise quantity by linear predictive coefficient using a three layered neural network, which is trained using three kinds of speech that is degraded by various background noises. In the experiment, the average values of the recognition results were 97.6% or more for various noises using Aurora2 database.

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A User based Collaborative Filtering Recommender System with Recommendation Quantity and Repetitive Recommendation Considerations (추천 수량과 재 추천을 고려한 사용자 기반 협업 필터링 추천 시스템)

  • Jihoi Park;Kihwan Nam
    • Information Systems Review
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    • v.19 no.2
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    • pp.71-94
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    • 2017
  • Recommender systems reduce information overload and enhance choice quality. This technology is used in many services and industry. Previous studies did not consider recommendation quantity and the repetitive recommendations of an item. This study is the first to examine recommender systems by considering recommendation quantity and repetitive recommendations. Only a limited number of items are displayed in offline stores because of their physical limitations. Determining the type and number of items that will be displayed is an important consideration. In this study, I suggest the use of a user-based recommender system that can recommend the most appropriate items for each store. This model is evaluated by MAE, Precision, Recall, and F1 measure, and shows higher performance than the baseline model. I also suggest a new performance evaluation measure that includes Quantity Precision, Quantity Recall, and Quantity F1 measure. This measure considers the penalty for short or excess recommendation quantity. Novelty is defined as the proportion of items in a recommendation list that consumers may not experience. I evaluate the new revenue creation effect of the suggested model using this novelty measure. Previous research focused on recommendations for customer online, but I expand the recommender system to cover stores offline.