• 한국조경학회지
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• 제44권1호
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• pp.66-79
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• 2016

본고는 정원 공간에 내재된 시간의 다원성에 대해 역대 시공간 이론을 다루면서 정원 공간에 적합한 시공간 이론 구축을 시도하였다. 구축된 이론을 바탕으로 문헌 분석을 통해 데릭 저먼의 정원을 대상으로 정원 공간의 객관적인 시간과 주관적인 시간, 이 두 가지에 초점을 두어 정원 공간의 내밀성을 분석하였다. 정원 공간에 속하는 시간을 객관적인 시간과 주관적인 시간으로 구분하였는데, 객관적인 시간은 생태적인 시간, 즉 지속성을 갖는 양화된 시간을 말하는 것이고, 주관적인 시간은 인간 주체의 의식에 따라 변하는 시간을 가리킨다. 또한 인간 주체의 감각에 의해 감정화된 시간도 포함한다. 우선 객관적인 시간의 관점에서 저먼의 정원 공간에 대해 해석하였다. 객관적인 시간 안에서 정원의 현재 공간 속에 저먼 개인의 감정에 따라 정원은 하나의 감성 공간으로 변모하면서 공간의 다층적인 속성을 보인다. 따라서 객관적인 시간 속에 존재하는 정원 공간은 결국 객관적이지 않고 인간 주체의 능동적인 감수에 따라 변모한다. 다음으로 주관적인 시간의 관점에서 저먼의 정원 공간을 고찰하였다. 저먼의 추억 속에 잠긴 정원 공간과 미래의 허상 속에서 연출되는 정원 공간은 저먼의 상상이나 자각에 따라 풍부한 의미를 내포한 공간으로 형성된다. 그러므로 주관적인 시간 속에서 정원 공간은 저먼의 의식에 따라 변모한다. 이상 연구를 통해 시간이 객관적인가 주관적인가의 여부에 관계없이 정원 공간은 물리적인 공간의 존재를 넘어서 인간주체의 의식이나 감정에 따라 무한한 공간을 연출할 수 있다는 것을 밝혔다. 정원 공간은 도시 공간과 달리 독특한 내밀성을 지닌 공간이기 때문에 본고는 기존의 정원 연구방법과 다른 시도를 통해 정원 공간의 독특성을 제시하여 보았다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.99-104
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• 2006

A semi-Lagrangian finite element scheme with objective time stepping algorithm for solving viscoelastic flow problem is presented. The convection terms in the momentum and constitutive equations are treated using a quasi-monotone semi-Lagrangian scheme, in which characteristic feet on a regular grid are traced backwards over a single time-step. Concerned with the generalized midpoint rule type of algorithms formulated to exactly preserve objectivity, we use the geometric transformation such as pull-back, push-forward operation. The method is applied to the 4:1 planar contraction problem for an Oldroyd B fluid for both creeping and inertial flow conditions.

• The Journal of Korean Physical Therapy
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• 제34권5호
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• pp.272-277
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• 2022

Purpose: This study compared the subjective and objective sleep quality between subjects with and without thoracic hyper-kyphosis. Methods: Forty participants were divided into a hyper-kyphosis (n=17) and normal group (n=17) by thoracic spinal angle measurement. The subjective sleep quality was measured using PSQI, a self-report, and objective sleep quality was measured using an actigraphy that measures time according to sleep patterns. Results: The PSQI scores of subjects with thoracic hyper-kyphosis were significantly higher than those with normal thoracic curvature (p=0.013). The total sleep time and real sleep time were less in subjects with hyper-kyphosis than in normal subjects (p=0.006; p=0.029). The light sleep time was less in subjects with excessive spondylolisthesis than in normal subjects (p=0.010). Light sleep time was less in those with hyper-kyphosis, but deep sleep time was similar to the subjects with a normal thoracic curvature (p=0.003; p=0.140). Conclusion: Subjects with thoracic hyper-kyphosis had a decrease in subjective sleep quality, such as sleep discomfort, and objective sleep quality, such as a decrease in sleep time compared to normal subjects.

• 한국태양에너지학회 논문집
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• 제31권6호
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• pp.111-124
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• 2011

The objective of this study is to develop the blind control strategy and method which reduce negative effect of incoming daylight on visual comfort of occupants, minimize psychological anxieties caused by frequent motions of a blind, and maximize positive effect of incoming daylight by opening/closing of a blind. In previous researches on blind controls, major problem is that the time interval and amount of blind movement do not meet the control objective at the inflected zone of solar profile curve. To overcome these limitations revealed in theprevious researches, following tasks were performed in this study. i)To establish the control objective to accomplish the goal of this study. ii)To develop the control methods and algorithms which prevent glare on the work-plane at any time and which control the time interval and amount of blind movement to follow the control objective at various solar profile angle curves. This study proposed the control strategy and method that define the base control section implying the inflection point within the control objective zone and subsequently, divide the control sections for the residual time zones. The proposed strategy and method are found to increase the incoming daylight and solar irradiation by 0 to 15 %.

• 한국컴퓨터정보학회논문지
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• 제24권1호
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• pp.167-178
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• 2019

In this paper, we study the multi-objectives vehicle and drone routing problem with time windows, MOVDRPTW for short, which is defined in an urban delivery network. We consider the dual modal delivery system consisting of drones and vehicles. Drones are used as a complement to the vehicle and operate in a point to point manner between the depot and the customer. Customers make various requests. They prefer to receive delivery services within the predetermined time range and some customers require fast delivery. The purpose of this paper is to investigate the effectiveness of the delivery strategy of using drones and vehicles together with a multi-objective measures. As experiment datasets, we use the instances generated based on actual courier delivery data. We propose a hybrid multi-objective evolutionary algorithm for solving MOVDRPTW. Our results confirm that the vehicle-drone mixed strategy has 30% cost advantage over vehicle only strategy.

• 한국멀티미디어학회논문지
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• 제16권1호
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• pp.50-55
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• 2013

This article presents a simple and reasonable in-service, real-time, and continuous single-ended objective video quality assessment model for DTV broadcasting using a multiburst signal at the bottom of the transient effect area, similar to Vertical Interval Test Signals. The issue of in-service video-quality monitoring in DTV broadcasting is addressed, and an effective method of quality monitoring is presented. The proposed method is also implemented and tested in a range of situations using a simulated HDTV broadcasting network.

• 정보처리학회논문지D
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• 제16D권3호
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• pp.295-306
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• 2009

질의실행시간최소화는 분산 데이타베이스 설계에 있어 가장 중요한 목적중의 하나이다. 총시간최소화는 온라인거래처리시스템의 목적인 반면, 반응시간최소화는 의사결정지원 질의시스템의 목적이다. 본 논문에서는 질의실행시간최소화를 달성하기 위해 질의를 세분화하여 최적의 데이터베이스 사이트에 할당하는 분석모델을 개발하였으며, 문제해결방법으로 유전자알고리즘을 채택하였다. 총시간최소화 관점에서의 질의실행 계획은 반응시간최소화 관점의 질의실행계획에는 적합하지 않다는 것을 증명하였으며, 그 반대의 경우도 증명하였다. 최대 20개의 조인이 포함되는 질의를 설계하여 시뮬레이션 실험을 통해 테스트를 수행하였고, 유전자알고리즘과 완전한 전수조사와의 결과를 비교함으로써 모든 경우에 유전자알고리즘을 채택한 해결책이 최적의 결과를 도출하였음을 증명하였다.

• Journal of Mechanical Science and Technology
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• 제18권8호
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• pp.1327-1337
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• 2004

An efficient multi-objective optimization method is presented making use of neural network and a systematic satisficing trade-off method (STOM), in order to simultaneously improve both maneuverability and durability of tire. Objective functions are defined as follows: the sidewall-carcass tension distribution for the former performance while the belt-edge strain energy density for the latter. A back-propagation neural network model approximates the objective functions to reduce the total CPU time required for the sensitivity analysis using finite difference scheme. The satisficing trade-off process between the objective functions showing the remarkably conflicting trends each other is systematically carried out according to our aspiration-level adjustment procedure. The optimization procedure presented is illustrated through the optimum design simulation of a representative automobile tire. The assessment of its numerical merit as well as the optimization results is also presented.

• 한국경영과학회지
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• 제37권1호
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• pp.19-28
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• 2012

We consider a multi-agent scheduling problem such that each agent tries to maximize the weighted number of just-in-time jobs. Two objectives are considered : the first is to find the optimal solution for one agent with constraints on the other agents' weight functions, and the second is to find the largest set of efficient schedules of which corresponding objective vectors are different for the case with identical weights. We show that when the number of agents is fixed, the single machine case with the first objective is NP-hard in the ordinary sense, and present the polynomial- time algorithm for the two-machine flow shop case with the second objective and identical weights.

• Journal of Construction Engineering and Project Management
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• 제4권4호
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• pp.33-40
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• 2014

Maximizing the profitability and minimizing the duration of construction projects in extreme weather regions is a challenging objective that is essential for project success. An optimization model is presented herein for the time-profit trade-off analysis of construction projects under extreme weather conditions. The model generates optimal/near optimal schedules that maximize profit and minimize the duration of construction projects in extreme weather regions. The computations in the model are organized into: (1) a scheduling module that develops practical schedules for construction projects, (2) a profit module that computes project costs (direct, indirect, and total) and project profit, and (3) a multi-objective module that determines optimal/near optimal trade-offs between project duration and profit. One example is used to show the impact of extreme weather on construction time and profit. Another example is used to show the model's ability to generate optimal trade-offs between the time and profit of construction projects under extreme weather conditions.