• Architectural research
• /
• v.7 no.2
• /
• pp.69-79
• /
• 2005

There are no formal decision tools or guidelines to assist owners and contractors in choosing delivery systems and project strategies that would allow for a radical reduction in project cycle time - from the preplanning phase through project start up. Therefore, it is important to identify the state-of-practice and the state-of-art on methods of achieving radical reduction defined as a reduction of 25% or more in overall project cycle time. A comprehensive literature review, three questionnaire surveys, and the seven case studies were conducted and the data obtained from them were analyzed to establish the state-of-practice and state-of-art for project cycle time reduction techniques.

• Architectural research
• /
• v.8 no.1
• /
• pp.57-68
• /
• 2006

Global competition and reduced project life cycle ultimately puts greater performance requirements on the capital project delivery systems used to maintain competitiveness. Despite continuing improvements in delivery cycle time, business owners of facilities continue to demand greater improvements in project delivery cycle time. Therefore, it is very important to investigate the various techniques and methods leading to reduction in project cycle time and also identify the applicability of identified techniques and methods. This paper introduces reduction techniques identified through literature review (i.e, Schedule Reduction Techniques (SRTs), Management Techniques (MTs), and Construction Institute Industry (CII) Best Practices (BPs). In order to collect applicability of these techniques under different project phases (Pre-project planning (PPP), Design (D), Material Management (MM), Construction (C), and Start-up (SU)), the Essence Applicability Matrices (EAM) is used.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.21 no.12
• /
• pp.695-702
• /
• 2009

Dynamic behavior of Libr-water absorption system using low-temperature hot water was investigated numerically. Thermal-hydraulic model of single-effect/double-lift 100 RT chiller was developed by applying transient conservation equations of total mass, Libr mass, energy and momentum to each component. Transient variations of system properties and transport variables were analysed during start-up operation. Numerical analysis were performed to quantify the effects of bulk concentration and part-load operation on the system performance in terms of cooling capacity, coefficient of performance, and time constant of system. For an absorption chiller considered in the present study, optimum bulk concentration was found to exist, which resulted in the minimum time constant with stable cooling capacity. COP and time constant increased as the load decreased down to 40%, below which the time constant increased abruptly and COP decreased as the load decreased further.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.46 no.4
• /
• pp.294-303
• /
• 2023

During wartime, the operation of engineering equipment plays a pivotal role in bolstering the combat prowess of military units. To fully harness this combat potential, it is imperative to provide efficient support precisely when and where it is needed most. While previous research has predominantly focused on optimizing equipment combinations to expedite individual mission performance, our model considers routing challenges encompassing multiple missions and temporal constraints. We implement a comprehensive analysis of potential wartime missions and developed a routing model for the operation of engineering equipment that takes into account multiple missions and their respective time windows of required start and completion time. Our approach focused on two primary objectives: maximizing overall capability and minimizing mission duration, all while adhering to a diverse set of constraints, including mission requirements, equipment availability, geographical locations, and time constraints.

• Journal of Digital Convergence
• /
• v.10 no.9
• /
• pp.195-212
• /
• 2012

Most of the office-workers are worrying about their future and try to make diverse future plan. Fast shifting industry pattern make office-workers retire early and their remain life time are getting longer and many of them try to consider some kind of new start-up. In this article factors affecting entrepreneurial intention were discussed such as individual factors, psychological factors, environmental factors. Individual factors were economic situations and future life expectation were analyzed. Psychological factors were composed of risk taking tendency, self efficiency, career value, and entrepreneurial characteristics were discussed. Environmental factors were composed of recognition on social-economic risks and recognition on negative mind on start-up, and employment unstability. 340 sample questionaries were collected and 26 samples were excluded. Data were analyzed by SPSS Win 18.0 Version. The results of the study were as follows. Among individual factors life-expectation after retirement was positive impact on entrepreneurial intention. Among psychological factors risk taking factor has positive impact on entrepreneurial intention. Among Environmental factors negative recognition on start-up has negative impact on entrepreneurial intention. Based on the studies diverse understanding and implementation of policies were necessary to change negative social atmospheres on start-up.

• Korean Journal of Applied Biomechanics
• /
• v.17 no.3
• /
• pp.31-39
• /
• 2007

The purpose of this study was to observe the kinematic pattern of elite women 100m hurdler race from start to finish and analyze how the change of horizontal velocity makes an influence on the athletes' performance. The analysis was based on the performance of Korean elite 100m hurdler A and international elite hurdlers B and C. Following results were drawn from the analyzation of elite 100m hurdlers' technical characteristics; During the race, hurdler A made more than 8 m/s of horizontal velocity at the 3rd, 4th, 6th, and the 7th hurdle. The horizontal velocity peaked at the 4th hurdle with 8.23 m/s. On the other hand, hurdler B and hurdler C maintained more than 8 m/s of horizontal velocity from the 2nd hurdle through the 10th hurdle. Hurdler B's fastest horizontal velocity was 8.67 m/s from the 6th to the 7th hurdle and hurdler C's fastest horizontal velocity was 8.85 m/s from the 5th to the 8th hurdle. From the start line to the 3rd hurdle, the times achieved by hurdlers A, B, and C were 4.90 sec, 4.65 sec, and 4.52 sec. In the middle of the race, which is from the 4th hurdle to the 7th hurdle, hurdlers A, B, and C ran in 9.10 sec, 8.60 sec, and 8.38 sec. And the latter part of the race to the 10th hurdle, the times hurdlers A, B, and C hit were 12.32 sec, 11.66 sec, and 11.32 sec. To the finish line, it took 1.15 sec for hurdler A, 1.1 sec for B, and 1.06 sec for C. Hence, to set the record of sub-13 sec, hurdler A should improve her acceleration from the start line to the 1st hurdle with the speed more than 5.4 m/s and should maintain more than 8 m/s of horizontal velocity from the 2nd hurdle through the 10th hurdle. In addition, hurdler A should improve her speed endurance to minimize the deceleration of horizontal velocity from the 4th hurdle to the final hurdle. If hurdler A could shorten 0.05 sec of time in each hurdle section, she would be able to set the record under 13 seconds.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.16 no.2
• /
• pp.1-17
• /
• 2021

Existing research on the investment relationship between venture capital and start-up companies has mainly focused on choosing a startup from the perspective of venture capital, an investor. However, as competition among venture capital has increased recently, excellent start-ups with proven technology are choosing venture capital in reversely. This study investigated key elements that affect the selection of the venture capital by a startup. To this end, we looked at which venture capital company was selected as the final investor for startups that have received investment proposals from multiple venture capitals at the same time. Six early start-ups(pre-series A/Series A) and five mid-term (Series B/C) start-ups were interviewed to focus on the influence of the three elements regarding venture capital - 1) venture capital reputation, 2) relationship between cofounders and investors, and 3) value adding service provided by venture capital - on choice. As a result of the research, the investment portfolio among the reputations of venture capital was a very important element in selecting venture capital. However, it has been shown that the age and asset under management of venture capital are not important. Relationships have emerged as a very important element. Finally, as for venture capital's value-adding services, start-ups in this study did not consider it important. In particular, consulting and monitoring by venture capital has been found to be a burdening attribute for startups. This study suggests implications that can increase the probability of successful investment by venture capital in the investment market where investment competition is fierce, and enhance mutual understanding between venture capital and startups.

• Journal of Korean Society of Transportation
• /
• v.12 no.1
• /
• pp.55-73
• /
• 1994

The objective of this research is to evaluate the pedestrian signal time involving green and flashing green times. The minimum pedestrian green indication should give time for pedestrian to start crossing safely, and the flashing green indication should give time to complete the crossing. An average pedestrian crossing speed of 1.1(m/s) was estimated by analyzing the field data which was slower than the 1.2(m/s) currently used. Furthermore, the study proposed that design speed for the flashing green time should be slow speed for considerations pedestrian safety, not the average speed. The 0.78-1.01(m/s) of pedestrian speed was estimated at the elementary school areas that indicated 0.2(m/s) slower than the other areas. The pedestrian starting time (perception/reaction time) and time headway from front to back of herd was estimated to determine minimum pedestrian green time. the pedestrian starting time was estimated to determine minimum pedestrian green time. The pedestrian starting time was ranged 2.52-4.29 seconds. The time interval between the pedestrian rows was found to be 1.25-1.86 seconds, which declines as the pedestrian rows increases, The equation to calculate the pedestrian signal, which declines as the pedestrian rows increases. The equation to calculate the pedestrian signal time is proposed using the pedestrian starting time, the time interval between the pedestrian rows, and pedestrian crossing speed given area types (commercial, business, mixed, and elementary school areas), number of both-directional pedestrians for a cycle, crosswalk length and width.

• Journal of Mechanical Science and Technology
• /
• v.20 no.4
• /
• pp.455-466
• /
• 2006

This study was an attempt to control and monitor Computerized Numerical Controller (CNC) machines anywhere and anytime for the development of a ubiquitous machine (u-machine). With a Personal Digital Assistant (PDA) phone, the machine status and machining data of CNC machines can be monitored in wired and wireless environments, including the environments of IMT2000 and Wireless LAN. Moreover, CNC machines can be controlled anywhere and anytime. The concept of the anywhere-anytime controlling and monitoring of a manufacturing system was implemented in this study for the purpose of u-manufacturing and u-machines. In this concept, the communication between the CNC controller and the PDA phone was successfully performed anywhere and anytime for the real-time monitoring and control of CNC machines. In addition, the interface between the CNC controller and the developed application module was implemented by Object linking and embedding for Process Control (OPC) and shared CNC memory. For communication, the design of a server contents module within the target CNC was based on a TCP/IP. Furthermore, the client contents module within the PDA phone was designed with the aid of embedded c++ programming for mobile communication. For the interface, the monitoring data, such as the machine status, the machine running state, the name of the Numerical Control (NC) program, the alarm and the position of the stage axes, were acquired in real time from real machines with the aid of the OPC method and by sharing the CNC memory. The control data, such as the start, hold, emergency stop, reserved start and reserved stop, were also applied to the CNC domain of the real machine. CNC machines can therefore be controlled and monitored in real time, anywhere and anytime. Moreover, prompt notification from CNC machines to mobile phones, including cellular phones and PDA phones, can be automatically realized in emergencies.

• Journal of the Korean Geographical Society
• /
• v.47 no.5
• /
• pp.641-653
• /
• 2012

We analyzed two radiocarbon-dated lagoonal sediment cores from Cheonjinho and Ssangho using various biogeochemical methods. As a result, the start times of rice agriculture are estimated to be AD 780 for Cheonjinho and 100 BC for Ssangho. There is a large temporal difference in the beginning of rice agriculture between two study sites even though they are closely located on the coast. This result indicates that pollen records are not sufficient to approximate the start time of rice agriculture accurately. A temporal lag seems to exist between the time when rice agriculture was first introduced and the time when full-scale rice agriculture began in the Yeongdong region, probably because of low agricultural productivity. In both study sites, rice agriculture intensified and slope erosion increased 250 years after full-scale agriculture began. This suggests that intensified rice agriculture resulted in an increased number of inhabitants, settlement expansion to hilly areas, and the consequent deforestation.