• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.12A
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• pp.1828-1835
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• 2000

In this paper, we analyzed the other-cell interference characteristics for various non-uniform traffic distributions and their effects on the capacity of multi-cell CDMA system. We consider three different traffic distributions, i.e., linear, exponential and Gaussian traffic distribution with distribution parameters. Changing the distribution parameter, we can obtain the center-focused distributions or uniform distributions for each model. From the results of other-cell interference calculation we can see that the other-cell interference decreases, as the user concentrates on the base station. Also using frequency reuse efficiency indicating the capacity reduction of a multi-cell system when compared to a single cell system, we evaluate the effect of traffic distribution on the reverse link CDMA capacity. For linear case, the capacity of multi-cell system is reduced to 0.637∼0.867 times that of single cell system. On the other hand, for both exponential and Gaussian cases, the capacity under a multi-cell environment is equal to 70∼100% of that under a single cell. Therefore, we conclude that the average capacity of multi-cell CDMA system are increased when users are likely to be at near the cell base station due to reduced total other-cell interference and decreased when users exist at near the cell edge regardless of traffic distribution models.

• Journal of Power System Engineering
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• v.10 no.3
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• pp.81-87
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• 2006

This paper deals with an empirical model for decoupling control to control the refrigeration system effectively. The conventional control schemes of the system are mainly focused on representative two control methods, superheat control and capacity control. The capacity control is basically conducted to respond partial loading conditions on the purpose of energy saving. The superheat control is mainly carried out to maintain maximum coefficient of performance (COP). In the variable speed refrigeration system, the capacity and the superheat are controlled by inverters and electronic expansion valves respectively for saving energy and improving cost performance. The capacity and superheat can not be controlled independently because of interfering loop when the compressor speed and opening angle electronic expansion valve is varied. Therefore, we suggest decoupling model to eliminate the interfering loop at first. Next, each transfer function in decoupling control model is obtained from number of experiments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10B
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• pp.1641-1647
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• 2000

This paper presents an analysis of coverage and capacity for the multi-layer CDMA cellular system. The multi-layer CDMA system that shares a common frequency band consists of macrocells for outdoor users and picocells for indoor users. Though macrocells and picocells interfere with each other the capacity of the whole system can be increased, We have analyzed the effect of muual interference upon cell coverage soft handover areas and capacities. The parameters involved in the engineering of the system are discussed. The study results sow that we can control the service coverage of indoor picocells with the system parameters set properly. It is also show that the capacity of the whole system that the capacity of the whole system can be enhanced smoothly by deploying the indoor picocells within existing macrocells.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.122-127
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• 2002

There are two methodologies to increase transport capacity of railway. The one is to invest railroad equipment or vehicles, and the other to improve operation efficiency through operation optimization. All of these is intended to increase transport capacity by improving line capacity. So far, we treat line capacity as the criteria for evaluating investment alternatives or for restricting train frequencies, and this criteria is calculated statical and experimental numerical formula. But, line capacity has special attribute that change dynamically according to operational condition, so there is a need of new line capacity estimation system. The Purpose of this paper is to present a new line capacity estimation system based on the probability simulation and its applications.

• Journal of the Korea Safety Management & Science
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• v.4 no.3
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• pp.167-175
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• 2002

There are two methodologies to increase transport capacity of railway. One is to invest railroad equipment or vehicles, and the other is to improve operation efficiency through optimization. All of these is intended to increase transport capacity by improving the line capacity. So far, we treat the line capacity as the criteria for evaluating investment alternatives or for restricting train frequencies, and this criteria is calculated statical and experimental numerical formula. But, line capacity has special attribute that changes dynamically according to operational conditions, so there is a need of new line capacity estimation system. The Purpose of this paper is to present a new estimation system of line capacity based on the probability simulation and its applications.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.55-58
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• 2007

An adaptive subcarrier allocation scheme based on comparative superiority of opportunity cost between groups is proposed for the enhancement of system capacity and its simple implementation at the base station of a multiuser OFDM system. The proposed algorithm is similar to the blockwise or the decentralized subcarrier allocation algorithm proposed by Xiaowen et al and Alen et al, respectively. In the proposed algorithm, however, all subcarriers are grouped according to the coherence bandwidth and the comparative superiority concept, which swaps the groups between users if the system capacity is increased, is adopted for the enhancement of system capacity. In addition, the proposed algorithm provides a simple solution for the conflict problem among users by reallocating only the conflicted groups and unassigned groups instead of reallocating entire groups. Simulation results demonstrate that the proposed algorithm increases the system capacity effectively over a static, an adaptive blockwise, and a decentralized subcarrier allocation algorithms.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1536-1541
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• 2003

In order to investigate the cooling and heating characteristics of a variable-capacity system A/C using a digital scroll compressor, the cooling and heating capacities and EER are measured by the psychrometric calorimeter. The capacity of the system is controlled by the digital scroll compressor, which is operated by controling PWM valve and the loading vs. unloading time. When the system A/C is operated under the cooling and heating standard conditions, EER is nearly uniform but cooling capacity and heating capacity increase at minimum, rated and maximum modes. When the auxiliary heater is on, at the cold region, the system A/C produces the excellent heating capacity.

• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.417-428
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• 2017

The micropile has been mainly used under the concept of supplementing structural support or reinforcing soft ground. For the micropiled-raft system which uses a micropile and a raft in combination in particular, it is generally considered as ground reinforcement rather than foundation components considering the bearing capacity of the micropile in many cases. In this study, the bearing capacity mechanism of the micropiled-raft system is investigated through a physical model test and numerical method. The numerical results have shown that not only the slender-pile-effect of the micropile, but also the ground reinforcement effect, increase the bearing capacity considerably. The bearing capacity formula of the micropiled-raft system is derived based on the failure mechanism obtained through model tests. The formula is verified and proposed as a design chart.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.3
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• pp.39-46
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• 1998

In the FDMA and TDMA Cellular Systems, call blocking rise when frewquence slots andtime slots are used to ther users. Otherwise, in the CDMA cellular systems, call locking arises when interference level is above 10dB according to call of other users. System capacity is defined to be Erlang capacity that is the number of users when CDMA blocking probability is 1% or 2%. Users number corresponded channel number of AMPS and TDMA cellular systems. In this paper, we proposed new reuse-fraction using square of interference poser and obtained Erlang capacity for reverse link of CDMA cellular system with bit rate $R_{b}$, 9.6kbps and 14.4kbps. As a results, Erlange capacity of CDMA system have more 20.7 and 5.5 times than AMPS and TDMA system and have more form 1 to 4 Erlang thatn Viterbi and Padovani obtaned.d.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.8
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• pp.2923-2943
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• 2021

The double helix structure of DNA makes it diverse, stable and can store information with high density, and these characteristics are consistent with the requirements of molecular communication for transport carriers. In this paper, a specific structure of molecular communication system based on DNA length coding is proposed. Transmitter (Tx) adopts the multi-layer golden foil design to control the release of DNA molecules of different lengths accurately, and receiver (Rx) adopts an effective and sensitive design of nanopore, and the biological information can be converted to the electric signal at Rx. The effect of some key factors, e.g., the length of time slot, transmission distance, the number of releasing molecules, the priori probability, on channel capacity is demonstrated exhaustively. Moreover, we also compare the transmission capacity of DNA-based molecular communication (DNA-MC) system and concentration-based molecular communication (MC) system under the same parameter setting, and the peak value of capacity of DNA-MC system can achieve 0.08 bps, while the capacity of MC system remains 0.025 bps. The simulation results show that DNA-MC system has obvious advantages over MC system in saving molecular resources and improving transmission stability.