• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.209-212
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• 2000

In this paper, effect of imperfect power control on performance of a pseudonoise (PN) code tracking loop is analyzed and simulated for a direct-sequence/code-division multiple access (DS/CDMA) system. The multipath fading channel is modeled as a two-ray Rayleigh fading model. Power control error is modeled as a log-normally distributed random variable. The tracking performance of DLL (delay-locked-loop) is evaluated in terms of tracking jitter and mean-time-to-lose-lock (MTLL). From the simulation results, it is shown that the PN tracking performance is very sensitive to the power control error.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.351-354
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• 1998

In this paper, we measured inter-floor loss in multifloored building to surround buildings at 910MHz. Effect of interfloor diffraction to propagate through out-surface were smaller than effect of reflection of surrounding buildings. If multifloored building were offered W-PBX service, we will have to design optimization of indoor cell to overcome time delay difference.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.218-219
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• 2002

In the past, the development of pharmacokinetic/pharmacodynamic (PK/PD) models for quantitating the time course of drug responses was mainly based on two types of models, the empirical effect compartment model that simply accounts for the delay between effect and plasma concentration (hysteresis) and the mechanism-based so-called indirect response model. The first approach traces back to a paper by Segre (1) and its application was popularized by Holford and Sheiner (2); indirect response models were introduced by Jusko's group (3). (omitted)

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.57-60
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• 1999

In many radio communication environments, there is a special component, called inter-symbol interference (ISI), mused by multipath time delay of signal and ISI components impose limitation of the data transmission rate. In this paper, we consider signaling pulse shapes, called partial response signaling (PRS), for minimizing the effect of ISI and show the improvement of performance by applying one of the partial-response signaling (PRS) pulses to two types of receiver system under dependent noise environments through the Monte-Carlo computer simulations.

• Journal of Korean Society of Transportation
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• v.24 no.7 s.93
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• pp.101-114
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• 2006

Recently due to the increase of cars and city life, the traffic congestion has worsened. It Is particularly worse in the center of the metropolis. Within the general public means, the public transport buses have the advantage of being more cheap, accessible and mobile. But as there is no separate lane for buses, the collision of cars and buses are creating damage to public service. In order to solve this situation, the bus priority signal system has been introduced to reduce the bus travel time and improve its services. The purpose of this study is to establish bus priority signal algorithm which builds bus efficiency under the real-time traffic signal control system and to analyze the effect of it. As the green time was calculated against real time (under the real-time traffic signal control system), compared to existing bus priority signal there was a reduction in cross street loss. The modified cycle was used to maintain signal progression. A case study was carried out using VISSIM simulation model. In result of this study, we found that there was a decrease in bus travel time despite some evidence of car delays and compared to existing bus priority signal the delay of dishonor could be reduced dramatically. The analysed result of person delay using MOE, is that there is evidence that when bus priority signal is in effect, the person delay is reduced.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.85-90
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• 2013

PID control for unstable processes with time delay is not easy to apply because of unstability due to the poles existing on left-hand side in s-plane and the effect of time delay. In this paper, the authors consider the PID controller design technique in case of predefining overshoot or rising time by designer according to control environment. To deal with constraint problem like this, in this paper, the RCGA incorporating the penalty strategy is used. This is the method that if the RCGA violates given constraints, the defined penalty function is summed to the evaluation function depending on the severity and then the given constraint problem is converted to non-constraints optimization problem. The proposed method is applied to the unstable FOPTD(First Order Plus Time Delay) system and simulations are accomplished to illustrate the set-point tracking performance.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.5
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• pp.312-325
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• 2006

Integration applications, such as EAI, B2Bi, need stable massive data processing systems during overload state cause by service request congestion in a short period time. In this paper, we propose the PLC (Peak Load Control)-based Worker-Linker pattern, which can effectively and stably process massive I/O transactions in spite of overload state generated by service request congestion. This pattern uses the delay time algorithm for the PLC mechanism. In this paper, we also show the example of applying the pattern to business-business integration framework and the experimental result for proving the stability of performance. According to our experiment result, the proposed delay time algorithm can stably control the heavy overload after the saturation point and has an effect on the controlling peak load.

• The Journal of the Acoustical Society of Korea
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• v.26 no.1
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• pp.32-41
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• 2007

The control room has been usually designed by the consideration of only one listening position for the sound engineer. By this study. many listening positions with the very similar acoustical condition were located in the specific region, so-called 'the reflection free zone', where the several engineer could evaluate the quality of sound at the same time. For constructing the reflection free zone, the control room has been designed by the concept of the $LEDE^{TM}$, and the initial time delay gap has been controled by the structure of control room and the properties of sound-absorbing materials. diffuser, Helmholtz resonator and image source of sound. The occurrence of any harmful phenomena like the standing wave, acoustic focusing. coloring. Hass effect and flutter echo, has greatly reduced in the reflection free zone.

• Design & Manufacturing
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• v.18 no.3
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• pp.71-80
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• 2024

Sink marks are a common defect that occurs due to differences in shrinkage in areas with significant thickness variations in injection-molded parts. In this paper, we investigated the reduction of sink marks and the improvement of gas venting in injection molding processes using External Gas Injection (EGI). A mold was designed with considerations for EGI core pins, O-ring grooves to prevent gas leakage, and ejector-pin sealing. The sink marks were then examined through a series of experiments. When the delay time for injecting compressed air was set to 2.2 seconds, the depth of the sink marks was minimized. However, when the delay time was either too short or too long, the depth of the sink marks increased. There was almost no difference in the depth of the sink marks at discharge pressures of 30 and 50 bar of compressed air, but the sink marks were significantly reduced at a discharge pressure of 70 bar. Under the conditions of a 2.2-second delay time and a supply pressure of 70 bar, the smallest depth, 0.594 ㎛, was observed when the supply time was between 6 and 7 seconds. This represents a reduction of approximately 94% compared to the sink mark depth of 10.078 ㎛ observed with conventional injection molding. To verify the gas venting effect of compressed air injection, an experiment was conducted using non-dried PC. The silver streaks that appeared on the exterior of the molded part were completely eliminated when the air supply pressure was set to 20 bar. This indicates that by injecting compressed air into the mold cavity before injecting the resin, the appearance quality of the injection-molded part can be improved without the need to dry the resin in advance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.707-712
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• 2013

In patients with acute myocardial infarction (AMI), the delay from symptom onset to hospital arrival has a critical effect on morbidity and mortality. This study examined to find out the determinants of the prehospital delay in patients with AMI. The study sample consisted of 597 patients hospitalized with AMI between Jan and Dec 2009. Demographic, medical history, and clinical data were abstracted from the hospital medical records of patients with confirmed AMI, the prehospital delay was categorized as less than or greater than 6 hours. Older age, low socioeconomic status(medical aid), and low use of Emergency medical system were associated with delays in seeking emergency care for Acute myocardial infarction. Education programs to improve patient knowledge of acute coronary syndrome symptoms and promote patient responsiveness with regard to seeking medical care should be used to reduce the prehospital delay time, especially in the low socioeconomic group.