• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.571-575
• /
• 2007

With intensive competition due to the limited growth of the domestic construction market volume and the opening and construction boom of international construction market, construction firms register to grope strategy of enterprise dimension for improvement such as entry extension of domestic construction market order corporate strategy and international construction market. In this research, influence factors of corporate strategy are extracted and their interrelationships are presented in the domain of change of external environment with the internal and external market system, construction enterprise's internal capacity and corporate strategy, government and the internal and external market. The result of this research will be used for quantitative analysis through system dynamics simulation and basic data of model effectiveness verification through actuality domestic construction enterprise's case study, and can be used to basic data of new corporate strategy establishment because construction enterprise forecasts effect hereafter establishing corporate strategy in construction environment that change rapidly.

• The KIPS Transactions:PartC
• /
• v.16C no.3
• /
• pp.373-382
• /
• 2009

we present more efficient method of a medium access for real-time ubiquitous sensor networks. Proposed MAC protocol is like the randomized CSMA/CA protocol, but unlike previous legacy protocols, it does not use a time-varying contention window from which a node randomly picks a transmission slot. To reduce the latency for the delivery of event reports from sensor nodes, we carefully decide to select a fixed-size contention window with non-uniform probability distribution of transmitting in each slot. We show that the proposed method can offer up to several times latency reduction compared to legacy of IEEE 802.11 as the size of the sensor network scales up to 256 nodes using a widely-used network simulation package, NS-2. We finally show that proposed MAC scheme comes close to meet bounds on the best latency being achieved by a decentralized CSMA-based MAC protocol for real-time ubiquitous sensor networks which is sensitive to latency.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.48 no.1
• /
• pp.33-43
• /
• 2011

This paper proposes a traffic-aware TXOP adjustment algorithm for the IEEE 802.11e networks. In the proposed algorithm the access point (AP) monitors the network traffics periodically and adjusts the TXOP value of the non-QoS traffic in order to improve the network throughput while maintaining the QoS of video and voice applications. The experimental results show that the proposed algorithm outperforms the legacy IEEE 802.11e in terms of the throughput and the fairness.

• Journal of Navigation and Port Research
• /
• v.27 no.4
• /
• pp.403-407
• /
• 2003

A basic concept of TAS(Tractor Appointment System), which not only enhances the terminal productivity, but also yields higher efficiency of domestic CT(Container Terminal), is developed in this paper for CT to more competitive and serviceable. To analyze the effects of TAS when applied to the existing four-tier CT, a quantitative analysis is performed. The results showed that the number of rehandling time of CT has been significantly decreased, the efficiency of CT increased, and the flow time of trucks in CT reduced in a great deal

• The Journal of Natural Sciences
• /
• v.1
• /
• pp.1-6
• /
• 1987

Pulse delays among operating lines are observed in a multiline operation transversely excited atmospheric pressure $CO_2$ laser which has an intracavity germanium etalon. To show the delay effect more precisely, we have replaced the etalon with a 40%/antireflecting coated ZnSe half mirror obtained two laser lines in which the delay can be controlled by a slight tilting of the output coupler, The results show that the individual rotational vibrational transition lines must have almost equal intensities in multiline oscillation in order to obtain high peak power and short pulses.

• Journal of the Korean Society for Railway
• /
• v.11 no.6
• /
• pp.588-595
• /
• 2008

This study is carried out for understanding mode choice behavior of shippers and introducing ideal mode share between rail and truck in Korea. The model type is individual behavioral model and the input data type is stated preference (SP) data. SP data was prepared by design of experiments. The explanatory variables in models are transport time, transport cost and service level. The research result shows that it is more effective to reduce transport cost rather than to implement other strategies. For container, reducing transport cost and transport time and increasing service level simultaneously can strengthen the competitiveness of rail over truck transportation. On the other hand, for bulk freight such as cement and steel, it is better to reduce the transport cost than to do other attributes.

• Annual Conference of KIPS
• /
• 2010.11a
• /
• pp.1053-1056
• /
• 2010

현재 센서 네트워크 시스템을 이용한 다양한 지능형 응용들에 대한 연구가 진행되고 있다. 일반적으로 센서 네트워크는 환경정보를 수집하기 위해 많이 활용된다. 최근 더욱 상세한 환경 모니터링이나 고품질 데이터에 대한 요구로 인해 멀티미디어 데이터의 요구가 증가하고 있다. 본 논문에서는 Zigbee 기반 센서 네트워크의 낮은 대역폭의 한계를 극복하고, 실시간 멀티미디어 데이터 전송을 위한 라우팅 기법에 대한 연구를 수행한다. 기존에 제안된 멀티미디어 데이터 전송 기법의 경우 비효율적인 다중경로 설정단계로 인해 경로설정 시간의 지연이 발생하고, Zigbee 의 대역폭 한계로 인해 낮은 데이터 전송속도를 보인다. 본 논문은 기존 기법의 대역폭 문제를 해결하는 블루투스와 Zigbee 하이브리드 라우팅 구조를 제안한다. 또한 경로설정 시간 지연 문제를 해결하는 경쟁기반 비-중첩 다중 경로 설정 기법을 제안한다. 제안하는 기법의 우수성을 비교평가하기 위해 시뮬레이션을 수행하였다. 그 결과 약 78% 지연시간이 감소되었으며, 통신 속도가 약 6.9 배 증가하였다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.7
• /
• pp.63-76
• /
• 2016

Most previous studies found a positive relationship between the value of a firm and its R&D investments. This research measures the impact of the timescale of the R&D investment of a firm on its value using panel vector autoregression. By measuring the time required for R&D to impact the value of a firm, this study demonstrates that the lead time is an essential factor in the analysis of the effect of R&D investment on a firm's value. Our study finds that the length of the lead time varies according to the firm's size, industry concentration, and book to market ratio. Firms with a higher industry concentration show a shorter lead time. Also, firms with a larger size and higher book to market ratio generally show a shorter lead time.

• The Journal of the Korea Contents Association
• /
• v.22 no.2
• /
• pp.593-604
• /
• 2022

This study examines how auditors respond to labor investment inefficiency, specifically its impact on audit fees and audit hours. Using a sample of Korean firms listed on the Korea Stock Exchange from 2003 to 2018, our empirical results indicate that firms involved in inefficient investment in labor incur higher audit fees and audit hours. This implies that auditors consider inefficient labor investment to cause considerable business risk, thus requesting higher external audit fees to compensate for higher audit risk. Furthermore, auditors expend more time and effort while auditing those firms by expanding the audit procedures to reduce the audit risk to an acceptable level. Finally, this study provides empirical evidence on whether the investment inefficiency in labor, an important factor in firms' competitiveness, incur higher audit fees as well as audit hours.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.10A
• /
• pp.912-921
• /
• 2005

Optical burst switching(OBS) is a promising solution for building terabit optical routers and realizing If over WDM. Channel scheduling Algorithm for reduce contention is one of the major challenges in OBS. We address the issue of how to provide basic burst channel scheduling in optical burst switched WDM networks with fiber delay lines(FDLs). In OBS networks the control and payload components or a burst are sent separately with a time gap. If CHP arrives to burst switch node, because using scheduling algorithm for data burst, reservation resources such as wavelength and transmit data burst without O/E/O conversion, because contention and void between burst are happened at channel scheduling process for data burst that happened the link utilization and bust drop probability Existent proposed methods are become much research to solve these problems. Propose channel scheduling algorithm that use Release Time of bust to emphasize clearance between data and data dissipation that is happened in data assignment in this treatise and maximize bust drop probability and the resources use rate (RTUC : Release Time Unscheduled Channel). As simulation results, Confirmed that is more superior in terms of data drop and link utilization than scheduling algorithm that is proposed existing. As simulation results, confirmed improved performance than scheduling algorithm that is proposed existing in terms of survival of burst, efficiency resource and delay. However, In case load were less, degradation confirmed than existent scheduling algorithm relatively, and confirmed that is superior in data drop aspect in case of load increased.