• Journal of the Korean Society of Tobacco Science
• /
• v.9 no.2
• /
• pp.59-68
• /
• 1987

This study was conducted to investigate the change of starch, total sugar, nicotine, and total nitrogen contents in green leaves at various stages of maturity(50-106 days after transplanting), and to relate between chemical constituents for flue-cured tobacco (Cv NC82 and BY 4). For the two cultivars and all stalk positions, starch contents increased with maturation, but decreased with senescence. Nicotine contents increased, while total nitrogen contents decreased with delay of harvest. Total sugar contents had a tendency of decrease. For the two cultivars , starch correlated negatively with total nitrogen, and positively with nicotine. Total nitrogen correlated negatively with nicotine. A delay of 5 to 7 days than conventional harvesting time would reach to the better ratio of the reducing sugar to nicotine ratio.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.305-310
• /
• 2001

The purpose of this study is to calculate delay damages for contractors. The study has been performed by investigation of delay cost occurrence status and the analysis of subway construction cases. The results of this study are as follows: 1. Delay cost( 1day) equivalent to $0.005\%$ of total construction cost by analysis case studies. 2. Including bank interest, dealy cost is analysed as the following; $1.1\~9.2\%$ of total construction cost in part extension period, $3.3\~11.0\%$ of total construction cost in total extension period. 3. In comparison between liquidated damages and delay cost, liquidated damages account for average 20.1 times of delay costs. 4. Acceleration cost will be calculate on the basis of delay cost calculation method. In the result of this method, acceleration cost is equal to delay cost at least or must be large than delay cost

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.24 no.2
• /
• pp.11-18
• /
• 2016

Global Positioning System (GPS) is currently widely used for aviation applications. Single-frequency GPS receivers are highly affected by the ionospheric delay error, and the ionospheric delay should be corrected for accurate positioning. Single-frequency GPS receivers use the Klobuchar model, whose model parameters are transmitted from GPS satellites. In this paper, the long-term accuracy of the Klobuchar model from 2002 to 2014 is analyzed. The IGS global ionosphere map is considered as true ionospheric delay, and hourly, seasonal, and geographical error variations are analyzed. Histogram of the ionospheric delay error is also analyzed. The influence of solar and geomagnetic activity on the Klobuchar model error is analyzed, and the Klobuchar model error is highly correlated with solar activity. The results show that the Klobuchar model estimates 8 total electron content unit (TECU) over the true ionosphere delay in average. The Klobuchar model error is greater than 12 TECU within $20^{\circ}$ latitude, and the error is less than 6 TECU at high latitude.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.9 no.6
• /
• pp.117-122
• /
• 2006

The objective of this study is to analyze the greenroof runoff quantity and delay. The experimental districts, have different soil thickness and vegetation, had installed. A measurement was conducted in Seoul University to investigate the runoff quantity and delay of the greenroof. The measurement point of runoff quality data were 8, located next to each experimental district. Also, the precipitation was measured by rain gauges(# RG2). The experimental investigation lasted from 21th July to 4th December, a total of 137 days. The results showed that the greenroof can contribute runoff retention and delay by soil, but the intensity of actual rain event affected the runoff reduction and delay. Overall, when was the rainy season, percent rainfall retention ranged 17.5% and runoff flow was delayed for 1-3 hours. But on the other hand, when was the typical rain event, percent rainfall retention ranged over 90% and runoff flow was delayed for 1-11 hours. In the result, the greenroof had the greatest runoff retention and delay, while for the typical rain event.

• Journal of Construction Engineering and Project Management
• /
• v.4 no.3
• /
• pp.33-46
• /
• 2014

Delay is the most common problem in the construction industry. It has many negative effects on project's success in terms of time, cost, quality, and safety. From the literature review, a total of thirty-five factors of delay were selected. These factors were divided into seven groups related to materials, manpower, owner, consultant, contractor, construction, and external problems. This study was carried out to identify the main causes of delay for a construction project through their importance level. The importance level was determined based on the frequency of occurrence and severity of impact. The structured questionnaire has distributed to the respondents who have much experience in construction management in Bangladesh. The results of analysis indicated that top five factors of construction delay according to their level of importance are: (1) price of construction materials increased very rapidly, (2) political situation (revolution/ public strikes), (3) shortages of skilled workers, (4) poor site management and supervision by contractor, (5) incompetent/ immature subcontractors. These findings of this study are expected to be significant contributions to Bangladesh construction industry in controlling current performance of project on time overrun.

• Journal of KIISE:Information Networking
• /
• v.29 no.4
• /
• pp.397-404
• /
• 2002

We propose a heuristic distributed unicast routing algorithm for minimizing the total cost of the path in a point to point network with do]ay constraint. The algorithm maintains a delay vector and a cost vector about the network states and finds the path using this information. In this paper, we show that our algorithm always finds a delay-constrained path if such a path exists and has O(│E│) message complexity(│E│is the number of links in the network). Also, simulation results show that the proposed algorithm has better cost performance than other delay-constrained routing algorithms.

• International Journal of Computer Science & Network Security
• /
• v.22 no.2
• /
• pp.167-174
• /
• 2022

Vehicular Ad hoc Networks are considered as special kind of Mobile Ad Hoc Networks. VANETs are a new emerging recently developed, advanced technology that allows a wide set of applications related to providing more safety on roads, more convenience for passengers, self-driven vehicles, and intelligent transportation systems (ITS). Delay Tolerant Networks (DTN) are networks that allow communication in the event of connection problems, such as delays, intermittent connections, high error rates, and so on. Moreover, these are used in areas that may not have end-to-end connectivity. The expansion from DTN to VANET resulted in Vehicle Delay Tolerant Networks (VDTN). In this approach, a vehicle stores and carries a message in its buffer, and when the opportunity arises, it forwards the message to another node. Carry-store-forward mechanisms, packets in VDTNs can be delivered to the destination without clear connection between the transmitter and the receiver. The primary goals of routing protocols in VDTNs is to maximize the probability of delivery ratio to the destination node, while minimizing the total end-to-end delay. DTNs are used in a variety of operating environments, including those that are subject to failures and interruptions, and those with high delay, such as vehicle ad hoc networks (VANETs). This paper discusses DTN routing protocols belonging to unicast delay tolerant position based. The comparison was implemented using the NS2 simulator. Simulation of the three DTN routing protocols GeOpps, GeoSpray, and MaxProp is recorded, and the results are presented.

• Journal of the Korean Society of Industry Convergence
• /
• v.4 no.1
• /
• pp.41-49
• /
• 2001

This study developed signal optimization algorithm by analyzing vehicle arrival patterns. The major principle of signal optimization is dissipate all queueing vehicle in 1cycle and assign delay time uniformly for all approaches. For this, this study used optimal green time and surplus green time. Optimal green time calculated by estimated traffic volume from vehicle arrival model. Surplus green time defined as the gap of optimal green time and queue dissipated time. And alternative cycle has minimum surplus green time was selected as the optimal cycle. Finally, total delay and average delay per vehicle can be calculated by using queueing theory.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.34S no.5
• /
• pp.25-34
• /
• 1997

Relatively slow tuning speed of optical device causes the unwanted delay in high speed single-hop multiwavelength networks. To lessen the overhead, we present a channel access protocol with dynamjic message scheduling. Th eframe structure of proposed protocol adopts hybrid multiaccess scheme in which WDMA is used as a basic multiaccess technique and TDMA is used to provide subchannels within a wavelength band. This architecture has two merits : the network extention is not limited by available number of wavelengths, and the transmission delay caused by optical device tuning time can to minimize the number of tunings. It schedules messages that require same wavelength channels sequencely, so the total transmission delay is reduced by decreasement of wavelength changes. The performance of proposed protocol is evaluated through numerical analysis based on probability and queueing theory. The peformance of proposed protocol is evaluated through numerical analysis based on probability and queueing theory. The numeric results show that the peformance of proposed protocol is better than that of previous one.

• Journal of Korean Institute of Industrial Engineers
• /
• v.22 no.2
• /
• pp.231-245
• /
• 1996

Semiconductor manufacturing line includes several batch processes which are to be controlled effectively to enhance the productivity of the line. The key problem in batch processes is a dynamic batch sizing problem which determines number of lots processed simultaneously in a single botch. The batch sizing problem in semiconductor manufacturing has to consider delay of lots, setup cost of the process, machine utilization and so on. However, an optimal solution cannot be attainable due to dynamic arrival pattern of lots, and difficulties in forecasting future arrival times of lots of the process. This paper proposes an efficient batch sizing heuristic, which considers delay cost, setup cost, and effect of the forecast errors in determining the botch size dynamically. Extensive numerical experiments through simulation are carried out to investigate the effectiveness of the proposed heuristic in four key performance criteria: average delay, variance of delay, overage lot size and total cost. The results show that the proposed heuristic works effectively and efficiently.