• 대한전자공학회논문지TC
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• 제43권3호
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• pp.126-134
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• 2006

현재 인터넷에서 널리 사용되고 있는 TCP는 대역폭과 지연의 곱이 큰 네트워크에서 특히 초기 시동단계를 포함하여 전반적으로 효율이 낮은 문제가 있다. 본 논문은 이 문제를 해결하기 위해 지연기반 혼잡제어(DCC: Delay-based Congestion Control) 방법을 제안한다. DCC는 선형과 지수 증가구간으로 나누어진다. 선형증가 구간은 기존의 TCP 혼잡회피 기법과 유사하며, 지수증가 구간은 혼잡에 의한 지연이 없는 경우 신속한 대역 확보를 위해 사용된다. 일반 TCP에서는 slow-start와 같은 지수증가 구간에서 대역과 지연의 곱으로 결정되는 크기의 버퍼가 제공되지 않는 경우 대역이 충분함에도 불구하고 손실이 발생하여 성능을 제한할 수 있다. 따라서 DCC에서는 RTT(Round Trip Time) 상태와 예측된 버퍼크기를 이용하여 지수증가 구간의 공급초과로 인한 손실을 방지하는 메카니즘을 제안한다. 시뮬레이션 결과를 통하여 대역과 지연의 곱이 큰 네트워크에서 DCC가 TCP에서 초기 시동시간과 throughput성능을 향상시킴을 보였다.

• 한국의류학회지
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• 제33권11호
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• pp.1707-1718
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• 2009

This study examines the effects of perceived risks on purchase decision behavior among Internet fashion consumers. The study survey used a self-administered questionnaire and a total data of 244 responses were used for analysis. The results of this study are as follows: First, the perceived risks consist of 6 factors, quality risk, counterfeit product risk, credit dealing risk, social/psychological risk, size and appearance risk, and delivery risk. The purchase decision behavior consist of 3 factors, delay of purchase decision, website switching, and offline conversion behavior. Second, purchase time positively affected the quality risk and credit dealing risk. Purchase frequency negatively affected the quality risk and credit dealing risk. Third, the quality risk, size and appearance risk, counterfeit product risk, and credit dealing risk positively affected the delay of purchase decisions. Quality risk and counterfeit product risk positively affected website switching. In addition, quality risk, social/psychological risk, and credit dealing risk positively affected the offline conversion behavior. Fourth, credit dealing risk negatively affected a short term purchase intention and the delivery risk negatively affected a long term purchase intention. The social/psychological risk and credit dealing risk negatively affected the repurchase intention.

• 한국세라믹학회지
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• 제48권1호
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• pp.106-109
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• 2011

In order to fabricate 8YSZ thick film by silk screen printing, YSZ(yttria-stabilized zirconia) commercial powder was used as starting materials. Paste for screen printing was made by mixing 8YSZ powder and organic vehicles. 8YSZ thick film was formed on $Al_2O_3$ substrate. The crystal structure, and microstructure were investigated. Grain size of 8YSZ was increased with increasing calcination temperature and rapid grain growth was shown after calcination at $1300^{\circ}C$. Microstructure showed the mixture of large and small grain size after $1400^{\circ}C$ sintering. Shrinkage rate of 8YSZ thick film sintered at $1400^{\circ}C$ was more than 40%.

• 한국정밀공학회지
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• 제27권4호
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• pp.63-71
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• 2010

Modular design is a very important design methodology that allows designers to develop a product family at low product development and production cost. This design methodology is also very powerful for products that require frequent design changes due to customer requirements. Most research on modular design is focused on the modularization based on functional decomposition, physical interface and manufacturing process of parts. In this paper, we propose a modularization method that takes size of human body parts into consideration for products which have physical interactions with the products such as office chairs and sport machines. Evaluation of modular design is based on dependence measurement between every pair of components in the design. In addition we proposed a module sizing method for the maximization of customer satisfaction in MC(Mass Customization) environment.

• Journal of Welding and Joining
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• 제19권4호
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• pp.384-390
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• 2001

There have been many problems due to deformation in industry field. Especially, it is severe in parts with small size and thin thickness and in products that must have excellent airtightness and anti-noise. The countermeasures for this deformation in field have mainly been dependent on the rule of trial and error by operator's experience because of productivities. Systematic study about this product with deformation is also insufficient that deformation is complex problem with shape, size, material of product, joining method and conditions, etc.. It is efficient to apply CAE technique without influence on productivity to this problem. There is, however much difference between the result analyzed by CAE and appearances in working field because of the insufficiency of communication between simulator and worker and of sensing data for boundary condition in analysis. In this study, to solve this deformation problem, we intend to make a simulation model that is adapted from working conditions by tuning and feedback between sensing data and simulation results. This paper include temperature monitoring and make a heat transfer model using sensing data in product as previous step for deformation analysis. The heat transfer analysis of shrinkage fit process is considerably difficult due to contact heat transfer between case and core. To solve this contact problem, gap element is used in present study.

• 경영과학
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• 제34권2호
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• pp.15-33
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• 2017

This paper considers a Bayesian Network analysis for understanding the heterogeneous cross-category effects of different promotion activities and developing an efficient overall promotion strategy for a large retail store. More specifically we differentiate price reduction promotion and floor promotion and study their heterogeneous effect on consumer purchase behavior under a market basket setting. We then utilize Bayesian networks in identifying complex association structure in market basket dataset by analyzing the effects of different promotional activities and also include the effects of time, family income and size. We find from our Bayesian network analysis that the dominant cross-category promotion effect of price promotion is the indirect effect whereas the dominant cross-category promotion effect of floor promotion is the direct effect. Also, among the demographic variables we find that family size of the household is linked with more product categories compared to income and see that there are differences in the extent of the effects by product category. Finally, we also show the existence of products acting as a network hub and how they can be utilized by retailers faced with a limited marketing budget and suggest a more efficient promotion strategy.

• 복식문화연구
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• 제31권5호
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• pp.692-704
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• 2023

This study analyzed 214 sports knee braces found on Chinese websites between October 2022 and November 2022 to assess product type (impact protection material, fastening method, and protection method), material composition, size, weight, and main characteristics. The product type was further categorized according to (1) use of hard guard and soft guard protection method; (2) cover type, strap type, and slip-on type fastening method; and (3) pressure type and support type protection method. It also noted the physical shock protection materials used, including foam (EVA or polyurethane) attached to joints as a buffer material and plastic (TPU or PP) that protects the user's knee from external impacts. The study found that the materials that primarily comprise sports knee braces are a combination of nylon, polyester, and neoprene. Additionally, it found that most sports knee braces available on the market are available in three sizes based on knee circumference: M (35-38cm), L (38-41cm), and XL (41-44cm), while some products are available in one size only. Furthermore, the majority of the 214 products studied weighed 200g, followed by 1,000g. Finally, in terms of product characteristics, many sports knee braces utilize ring-shaped silicone pads to distribute the load pressure on the knees or incorporate sturdy adhesive velcro to improve knee stability.

• Asia pacific journal of information systems
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• 제29권2호
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• pp.203-216
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• 2019

There is an accuracy-diversity dilemma with personalized recommendation services. Some researchers believe that accurate recommendations might reinforce customer satisfaction. However, others claim that highly accurate recommendations and customer satisfaction are not always correlated. Thus, this study attempts to establish the causal factors that determine customer satisfaction with personalized recommendation services to reconcile these incompatible views. This paper employs statistical analyses of simulation to investigate an accuracy-diversity dilemma with personalized recommendation services. To this end, we develop a personalized recommendation system and measured accuracy, diversity, and customer satisfaction using a simulation method. The results show that accurate recommendations positively affected customer satisfaction, whereas diverse recommendations negatively affected customer satisfaction. Also, customer satisfaction was associated with the recommendation product size when neighborhood size was optimal in accuracy. Thus, these results offer insights into personalizing recommendation service providers. The providers must identify customers' preferences correctly and suggest more accurate recommendations. Furthermore, accuracy is not always improved as the number of product recommendation increases. Accordingly, providers must propose adequate number of product recommendation.

• Advances in concrete construction
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• 제13권6호
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• pp.433-450
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• 2022

The conventional disposal methods of waste tires are harmful to the environment. Moreover, the recycling/reuse of waste tires in domestic and industrial applications is limited due to parent product's quality control and environmental concerns. Additionally, the recycling industry often prefers powdered rubber particles (<0.60 mm). However, the processing of waste tires yields both powdered and coarser (>0.60 mm) size fractions. Reprocessing of coarser rubber requires higher energy increasing the product cost. Therefore, the waste tire rubber (WTR) less favored by the recycling industry is encouraged for use in construction products as one of the environment-friendly disposal methods. In this study, WTR fiber >0.60 mm size fraction is collected from the industry and sorted into 0.60-1.18, 1.18-2.36-, and 2.36-4.75-mm sizes. The effects of different fiber size fractions are studied by incorporating it as fine aggregates at 10%, 20%, and 30% in the self-compacting rubberized concrete (SCRC). The experimental investigations are carried out by performing fresh and hardened state tests. As the fresh state tests, the slump-flow, T500, V-funnel, and L-box are performed. As the hardened state tests, the scanning electron microscope, compressive strength, flexural strength and split tensile strength tests are conducted. Also, the water absorption, porosity, and ultrasonic pulse velocity tests are performed to measure durability. Furthermore, SCRC's energy absorption capacity is evaluated using the falling weight impact test. The statistical significance of content and size fraction of WTR fiber on SCRC is evaluated using the analysis of variance (ANOVA). As the general conclusion, implementation of various size fraction WTR fiber as fine aggregate showed potential for producing concrete for construction applications. Thus, use of WTR fiber in concrete is suggested for safe, and feasible waste tire disposal.

• 한국의류학회지
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• 제39권3호
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• pp.408-418
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• 2015

This study investigates the purchasing and wearing conditions of wetsuits, and analyzes consumer awareness on wetsuit functional factors between domestic and imported brands. This research provides basic information on presenting competitiveness and developing suitable wetsuits for the Korean body shape through an investigation of a size system. An in-depth interview was conducted to consider consumer awareness with 10 persons of different levels of scuba diving experience. The survey variables consist of classified suggestion of inquires for functional factors and size systems. We distributed 80 questionnaires to scuba diving club members; subsequently, a total of 66 usable data sets were coded for statistical analysis through SPSS WIN 18.0. The result shows that respondents preferred imported ready-to-wear brands, whereas national ready-to-wear brands were purchased less often. However, the difference in customer awareness of functional factors between domestic and imported brands was not significant. In evaluating the size system of six brands (including three domestic and three imported brands), wetsuits of domestic brands were better fitted to the Korean body shape than imported brands; however, competitiveness has been hindered by public perception that domestic brands imitate imported brands. The results suggest that domestic brands can strengthen their competitiveness through promoting a lower price and size suited to Koreans while trying to change public perception as imitators of imported brands.