• ETRI Journal
• /
• v.30 no.2
• /
• pp.238-248
• /
• 2008

At the extremes of the complexity-performance plane, there are two exemplary QoS management architectures: Integrated Services (IntServ) and Differentiated Services (DiffServ). IntServ performs ideally but is not scalable. DiffServ is simple enough to be adopted in today' core networks, but without any performance guarantee. Many compromise solutions have been proposed. These schemes, called quasi-stateful IntServ or stateful DiffServ, however, have not attracted much attention due to their inherently compromising natures. Two disruptive flow-based architectures have been recently introduced: the flow-aware network (FAN) and the flow-state-aware network (FSA). FAN's control is implicit without any signaling. FSA's control is even more sophisticated than that of IntServ. In this paper, we survey established QoS architectures, review disruptive architectures, discuss their rationales, and points out their disadvantages. A new QoS management architecture, flow-aggregate-based services (FAbS), is then proposed. The FAbS architecture has two novel building blocks: inter-domain flow aggregation and endpoint implicit admission control.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.41 no.1
• /
• pp.87-98
• /
• 2016

A single machine scheduling problem for jobs with stochastic processing time is considered in this study. Shortest processing time (SPT) sequencing according to the expected processing times of jobs is optimal for schedules with minimal expected mean flow time when all the jobs arrive to be scheduled and their expected processing times are known. However, SPT sequencing according to the expected processing time may not be optimal for the minimization of the mean flow time when the actual processing times of jobs are known. This study evaluates the complexity of SPT sequencing through a comparison of the mean flow times of schedules based on the expected processing times and actual processing times of randomly generated jobs. Evaluation results show that SPT sequencing according to the expected flow time exhibits chaotic variation to the optimal mean flow time. The relative deviation from the optimal mean flow time increases as the number of jobs, processing time, or coefficient of variation increases.

• Fire Science and Engineering
• /
• v.32 no.4
• /
• pp.69-74
• /
• 2018

This study developed a ventilation damper that can control flow rate according to pressure differential variation of the smoke control room in order to improve problems related to existing smoke management systems and maximizing performance of smoke management systems. The development damper was tested for verification of utility and performance. The supply flow of the developed ventilation damper was increased by about 1 to 5%. The results prove the effectiveness of the flow control ventilation damper by providing stable flow over the designed flow of the fan in the smoke control room. In addition, the study acquired the original technology for a flow control ventilation damper.

• Journal of Construction Engineering and Project Management
• /
• v.3 no.1
• /
• pp.1-9
• /
• 2013

Construction is a competitive industry and successful contractors must be able to win bids to obtain projects. Cash flow analysis not only determines actual profit at the end of the project, but also estimates required cash resources or cash ballances at the end of every month. Cash flow analysis is important in managing a construction project; however, it requires extensive information that is not immediately available to the general contractor. Before contractors can perform cash flow analysis, they must first complete a series of pre-requisites such as the quantity take off, scheduling, and cost estimating, followed by accurate assessments of project costs incurred and billable progress made. Consequently, cash flow analysis is currently a lengthy, uncertain process. This paper suggests improved cash flow analysis can be developed using data extraction in Building Information Modeling (BIM). BIM models contain a wealth of information and tools have been developed to automate a series of process such as quantity takeoff, scheduling, and estimating. This paper describes a prototype tool to support BIM-based, automated cash flow analysis.

• Journal of Environmental Science International
• /
• v.26 no.8
• /
• pp.939-953
• /
• 2017

For the development of flow duration curves for the management of 41 Total Maximum Daily Load (TMDL) units of the Nakdong River basin, first, an equation for estimating daily flow rates as well as the level of correlation (correlation and determination coefficients) was extrapolated through regression analysis of discrete (Ministry of Environment) and continuous (Ministry of Land, Infrastructure and Transportation) measurement data. The equation derived from the analysis was used to estimate daily flow rates in order to develop flow duration curves for each TMDL unit. By using the equation, the annual flow duration curves and flow curves, for the entire period and for each TMDL unit of the basin, were developed to be demonstrated in this research. Standard flow rates (abundant-, ordinary-, low- and drought flows) for major flow duration periods were calculated based on the annual flow duration curves. Then, the flow rates, based on percentile ranks of exceedance probabilities (5, 25, 50, 75, and 95%), were calculated according to the flow duration curves for the entire period and are suggested in this research. These results can be used for feasibility assessment of the set values of primary and secondary standard flow rates for each river system, which are derived from complicated models. In addition, they will also be useful for the process of implementing TMDL management, including evaluation of the target level of water purity based on load duration curves.

• The Journal of the Korea Contents Association
• /
• v.22 no.5
• /
• pp.643-655
• /
• 2022

The purpose of this study was to verify the moderating effect of parental learning involvement in the effect of adolescents' time management ability on face-to-face and non-face-to-face learning flow. The participants were 363 middle and high school adolescents, and data were collected through an online survey. The main statistical analysis methods were ANOVA, correlation analysis, and regression analysis. The major findings were as follows. First, learning flow was significantly higher in the face-to-face class than in the non-face-to-face class. Second, there was a statistically significant positive correlation among time management ability, parental involvement in learning, and learning flow. Third, in the effect of time management ability on face-to-face learning flow, the moderating effect of parental learning involvement was statistically significant. Fourth, in the effect of time management ability on non-face-to-face learning flow, the moderating effect of parental learning involvement was statistically significant. In other words, the higher the positive parental involvement in learning, the stronger the effect of adolescents' time management ability on learning flow. Finally, the importance of positive parental involvement for the improvement of adolescents' learning flow and methods of enhancing time management ability were discussed.

• Journal of Korean Society on Water Environment
• /
• v.28 no.4
• /
• pp.574-581
• /
• 2012

It is important to analyze the status of water quality with relation to the stream flow to attain water quality goal more effectively in the unit watersheds for the management of Total Maximum Daily Loads (TMDLs). This study developed a flow duration-water quality distribution graph to figure out water quality appearances on the flow variation and analyzed contributions of water quality observations to the impaired water bodies quantitatively by hydrologic conditions. Factors relating to water quality variation can be analyzed more precisely and assessed on the base of quantified contributions. It is considered that this approach could be utilized to establish a more effective plan for the water quality improvement including the prioritization of pollution reduction options.

• Proceedings of the KAIS Fall Conference
• /
• 2009.05a
• /
• pp.319-324
• /
• 2009

Lately, knowledge-based society comes, it is important for enterprises to creatively utilize knowledge of technology for technological innovation. So, Technological innovation capacity of enterprises is important factor of business success. To improve technological innovation capacity, enterprises should well utilize their internal knowledges and external knowledges which come from technological diffusion. To well utilize external knowledges of enterprises they should well understand external knowledge flow. Especially knowledge flow also occurs frequently between nations, understanding of knowledge flow which occurs between nations is important to improve nation`s technological innovation capacity. So this paper presents comparison of technological innovation capacity and knowledge diffusion flow between nations.

• International conference on construction engineering and project management
• /
• 2011.02a
• /
• pp.556-560
• /
• 2011

Players of construction projects proceed with each work process by information gathering, modification and communication. Due to the complex and long-span lifecycle projects increased, it became more important to grasp this mechanism for the successful project performance in construction project. Hence, most project information management systems or knowledge management systems equip information retrieval system. There are two logic to infer the meaning of retrieval target; inductive reasoning and deductive reasoning. The former is based on metadata explaining the target and the later is based on relation between data. To infer the information flow, it is necessary to define the correlation between players and work processes. However, most established information retrieval systems are based on index search system and it is not focused on correlation between data but data itself. Thus, this research aims to research on process of information flow retrieval system for large-scale construction projects.

• 유체기계공업학회:학술대회논문집
• /
• 2006.08a
• /
• pp.199-202
• /
• 2006

The objective of this study is to propose methods of controlling the wake behind a sphere for drag reduction using the suboptimal control theory and surrogate management framework, respectively. The Reynolds numbers considered is 300 at which the base flow is unsteady planar symmetric. Given the cost function defined as the square of the difference between the target pressure (potential-flow pressure) and real flow pressure on the sphere surface, the suboptimal control makes the flow steady axisymmetric and produces drag reduction. Based on the actuation profile from the suboptimal control, the optimal wavy actuation profile is obtained using the surrogate management framework and produces drag reduction.