• The Journal of Engineering Research
• /
• v.7 no.1
• /
• pp.105-117
• /
• 2005

Because of the recent boost of the application services utilizing electronic tags, researches about the electronic tag management are widely being proceeded. In order to manage the object information collected from various electronic tags XML based data process, which is widely used on the web, is being demanded. Thus, in this paper, we are defining the re-usable object typer that is often used in this business area. Utilizing both the data type we defined and the Core Event Type defined from EPCIS Spec, we designed the scheme matching the object data model of merchant shipping field.

• Journal of information and communication convergence engineering
• /
• v.9 no.4
• /
• pp.385-390
• /
• 2011

In this paper, various ultra-wideband (UWB) spatial multiplxing (SM) multiple input multiple output (MIMO) receivers based on a prerake diversity combining scheme are discussed and their performance is analyzed. Several UWB MIMO detection approaches such as zero forcing (ZF), minimum mean square error (MMSE), ordered successive interference cancellation (OSIC), sorted QR decomposition (SQRD), and maximum likelihood (ML) are considered in order to cope with inter-channel interference. The UWB SM systems based on transmitter-side multipath preprocessing and receiver-side MIMO detection can either boost the transmission data rate or offer significant diversity gain and improved BER performance. The error performance and complexity of linear and nonlinear detection algorithms are comparatively studied on a lognormal multipath fading channel.

• International Journal of Computer Science & Network Security
• /
• v.22 no.4
• /
• pp.394-400
• /
• 2022

The radio resources available in a wireless network system are limited. Therefor, job of managing resources is not easy task. Because the resources are shared among the UEs that are connected, the process of assigning resources must be carefully controlled. The packet scheduler in an LTE network is in charge of allocating resources to the user equipment (UE). Femtocells networks are being considered as a promising solution for poor channel performance for mulitple environments. The implementation of femtocells into a macrocell (traditional base station) would boost the capacities of the cellular network. To increase femtocells network capacity, a reliable Packet Scheduler mechanism should be implemented. The Packet Scheduler technique is introduced in this paper to maximize capacity of the network while maintaining fairness among UEs. The proposed solution operates in a manner consistent with this principle. An analysis of the proposed scheme's performance is conducted using a computer simulation. The results reveal that it outperforms the well-known PF scheduler in terms of cell throughput and average throughput of UEs.

• International Journal of Computer Science & Network Security
• /
• v.22 no.4
• /
• pp.292-298
• /
• 2022

Femtocell networks can be a potential method for increasing the capacity of LTE networks, especially in indoor areas. However, unplanned deployment of femtocells results in co-tier interference and cross-tier interference problems. The interference reduces the advantages of implementing femtocell networks to a certain extent. The notion of Fractional Frequency Reuse (FFR) is proposed in order to reduce the impact of interference on the system's performance. In this paper, a dynamic approach for efficiently partitioning the spectrum is suggested. The goal is to enhance the capacity of femtocells, which will improve the performance of the system. The suggested strategy allocates less resources to the macrocell portion of the network, which has a greater number of femtocells deployed to maximize the utilization of available resources for femtocell users. The spectrum division would be dynamic. The proposed strategy is evaluated through a simulation using MATLAB tool. In conclusion, the results showed that the proposed scheme has the potential to boost the system's capacity.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.701-708
• /
• 1998

This paper presents a novel non-resonant PWM DC-DC converter for X-ray high-voltage power generator using the parasitic impedances of the high-voltage high-frequency link transformer with its output high-voltage control scheme and steady-state characteristics compared to the conventional series-parallel resonant DC-DC converter. The key point of this approach is to evaluate effectiveness of reduction of the turn ratio of the high-voltage high-frequency transformer on improvements in power conversion efficiency and the power factor applying a boost AC-DC converter as DC voltage source, especially in the long exposure term and light output load ranges.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.44 no.5
• /
• pp.62-70
• /
• 2007

In this paper, the boost Power Factor Correction(PFC) technique for Direct Torque Control(DTC) of brushless DC motor drive in the constant torque region is implemented on a TMS320F2812DSP. Unlike conventional six-step PWM current control, by properly selecting the inverter voltage space vectors of the two-phase conduction mode from a simple look-up table at a predefined sampling time, the desired quasi-square wave current is obtained, therefore a much faster torque response is achieved compared to conventional current control. Furthermore, to eliminate the low-frequency torque oscillations caused by the non-ideal trapezoidal shape of the actual back-EMF waveform of the BLDC motor, a pre-stored back-EMF versus position look-up table is designed. The duty cycle of the boost converter is determined by a control algorithm based on the input voltage, output voltage which is the dc-link of the BLDC motor drive, and inductor current using average current control method with input voltage feed-forward compensation during each sampling period of the drive system. With the emergence of high-speed digital signal processors(DSPs), both PFC and simple DTC algorithms can be executed during a single sampling period of the BLDC motor drive. In the proposed method, since no PWM algorithm is required for DTC or BLDC motor drive, only one PWM output for the boost converter with 80 kHz switching frequency is used in a TMS320F2812 DSP. The validity and effectiveness of the proposed DTC of BLDC motor drive scheme with PFC are verified through the experimental results. The test results verify that the proposed PFC for DTC of BLDC motor drive improves power factor considerably from 0.77 to as close as 0.9997 with and without load conditions.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.2
• /
• pp.328-338
• /
• 2017

In this paper, a zero torque control scheme adopting current sharing function (CSF) used in integrated Switched Reluctance Motor (SRM) drive with DC battery charger is proposed. The proposed control scheme is able to achieve the keeping position (KP), zero torque (ZT) and power factor correction (PFC) at the same time with a simple novel current sharing function algorithm. The proposed CSF makes the proper reference for each phase windings of SRM to satisfy the total charging current of the battery with zero torque output to hold still position with power factor correction, and the copper loss minimization during of battery charging is also achieved during this process. Based on these, CSFs can be used without any recalculation of the optimal current at every sampling time. In this proposed integrated battery charger system, the cost effective, volume and weight reduction and power enlargement is realized by function multiplexing of the motor winding and asymmetric SR converter. By using the phase winding as large inductors for charging process, and taking the asymmetric SR converter as an interleaved converter with boost mode operation, the EV can be charged effectively and successfully with minimum integral system. In this integral system, there is a position sliding mode controller used to overcome any uncertainty such as mutual inductance or DC offset current sensor. Power factor correction and voltage adaption are obtained with three-phase buck type converter (or current source rectifier) that is cascaded with conventional SRM, one for wide input and output voltage range. The practicability is validated by the simulation and experimental results by using a laboratory 3-hp SRM setup based on TI TMS320F28335 platform.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.8
• /
• pp.1560-1566
• /
• 2017

Recently, accumulation of data on pig farm is enabled through the wide spread of smart pig farm equipped with Internet-of-Things based sensors, and various machine learning algorithms are applied on the data in order to improve the productivity of pig farm. Herein, multiple machine learning schemes are used to predict the water usage in pig farm which is known to be one of the most important element in pig farm management. Especially, regression algorithms, which are linear regression, regression tree and AdaBoost regression, and classification algorithms which are logistic classification, decision tree and support vector machine, are applied to derive a prediction scheme which forecast the water usage based on the temperature and humidity of pig farm. Through performance evaluation, we find that the water usage can be predicted with high accuracy. The proposed scheme can be used to detect the malfunction of water system which prevents the death of pigs and reduces the loss of pig farm.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.2
• /
• pp.790-802
• /
• 2017

This paper proposes the modeling and control strategy to track the MPPs of hybrid PV and Wind power systems, using a new dual input boost converter. The dual input power conditioning system with an independent MPPT control scheme is introduced with minimum number of circuit elements in order to reduce the switching loss, size and cost of the system. Since the operating conditions for the PV and Wind power systems are very distinct from each other, an efficient and superior control system is required to track the MPPs of both renewable sources with the use of a simply-structured single-ended single-inductor converter. The design of Power-Conditioning System (PCS) and detail control strategy are presented in this paper. To provide independent tracking of MPPs, a variable duty-cycle control strategy is employed for the wind system and a variable frequency strategy is employed for the PV system. Finally, the proposed dual-input converter for hybrid power conditioning system is implemented and the hardware test results are presented. From the hardware experiment, it is concluded that the proposed system successfully tracks the MPPs of both of the renewable power systems independently.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.32 no.1
• /
• pp.92-103
• /
• 2004

This design was submitted to an invited competition for the Ski Resort of Kangwon Land which was held by Kangwon Land Resort in August, 2003. The site is located at 1∼17 Gohan-ri Gohan-eup Jungsungun Kangwon-do and has an area of 5,000,000$m^2$. The objectives of this project were to revitalize the local economy of Sabuk, Gohan which is well Down for deserted coal mines, by creating a resort complex for family group users with an environmentally friendly ski facility. This design scheme addresses three areas of concerns: First, how to boost the local economy through the proposed ski resort. By limiting lodging facilities in the ski resort, we could induce more development in the nearby towns. In order to balance the economical benefit to towns of Sabuk and Gohan, we decided to have two separate ski base facilities in each town boundary. Second, how to encourage family-oriented use of the ski resort by designing user-friendly ski slope, especially for beginner skiers. We designed 50% more beginner-level ski slope compared to average ski resorts. Third, how to make environmentally-friendly ski resort by respecting the original land form. We minimized the damage to the natural environment by protecting valuable tree groves. Also, ski slopes are designed to reduce unnecessary earth movement. This was designed under the assumption that more valley-oriented slopes would result in less cutting and banking of earthwork； this assumption was verified in comparison with other ski resorts. It is expected that this desist would serve environmentally-friendly designs in ski slopes.