• Journal of Radiation Protection and Research
• /
• v.48 no.1
• /
• pp.9-14
• /
• 2023

Background: The detectors of both computed radiography (CR) and direct digital radiography (DR) have a wide dynamic range that could tolerate high values of exposure factors without an adverse effect on image quality. Therefore, this study aims to assess patient radiation dose and proposes institutional diagnostic reference levels (DRLs) for two teaching hospitals in Ghana. Materials and Methods: CR and DR systems were utilized in this study from two teaching hospitals. The CR system was manufactured by Philips Medical Systems DMC GmbH, while the DR system was manufactured by General Electric. The entrance skin doses (ESDs) were calculated using the standard equation and the tube output measurements. Free-in-air kerma (µGy) was measured using a calibrated radiation dosimeter. The proposed institutional DRLs were estimated using 75^th percentiles values of the estimated ESDs for nine radiographic projections. Results and Discussion: The calculated DRLs were 0.4, 1.6, 3.4, 0.5, 0.4, 1.1, 1.0, 1.2, and 1.7 mGy for chest posteroanterior (PA), lumbar spine anteroposterior (AP), lumbar spine lateral (LAT), cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively in CR system. In the DR system, the values were 0.3, 1.6, 3.1, 0.4, 0.3, 0.7, 0.6, 0.9, and 1.3 for chest PA, lumbar spine AP, lumbar spine LAT, cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively. Conclusion: Institutional DRLs in nine radiographic projections have been proposed for two teaching hospitals in Ghana for the first time. The proposed DRLs will serve as baseline data for establishing local DRLs in the hospitals and will be a valuable tool in optimizing patient doses.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.05a
• /
• pp.584-588
• /
• 2021

The impedance of the speaker is likely to be recognized as a fixed value. However, speaker impedance continues to vary with frequency variation, especially larger in resonant frequency region. The sound pressure level of loudspeakers is determined by the current flowing throughout the coil that consists loudspeakers. If loudspeakers are driven by voltage, sound pressure level of the loudspeaker is distorted by the variation of loudspeaker impedance. Current-drive of loudspeakers can solve this problem, but distortion of sound pressure level occurs in low frequencies due to resonance. The distortion can degrade the sound quality of the sound system. So to solve this problem, In this paper, we propose a resonance compensation circuit using DSP. we simulates audio systems using an equivalent model of loudspeakers to verify distortion of sound pressure level due to impedance variation and propose a circuit to compensate it. The proposed circuit is configured using a state variable filter and it can adjust the center frequency and output, so it will be used various sound systems.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.28-28
• /
• 2022

This paper presents the first genome assemblies of Philippine mangoes that provide valuable reference for varietal improvement and genomic studies on mango and related fruit crops. WE sequenced whole genomes of3 species, Mangifera odorata (Huani), Mangifera altissima (Paho), and Mangifera indica 'Carabao' (Sweet Elena). 'Carabao' is the major export variety of the Philippines; Paho is identified as vulnerable by the IUCN Red List of Threatened Species; Huani has fruit sap acrid which is the primary defense mechanism against insects and birds. We used Falcon, a diploid aware -de novo assembler to assemble SMRT generated long-read sequences. Falcon-unzip was employed to phase the output assembly producing larger contig sets (primary contigs) and shorter contigs corresponding to haplotypes (haplotigs). Assembly statistics were generated by comparing the assembly to a reference genome, Tommy Atkins, using Quality Assessment Tool (QUAST). Moreover, the extent of duplication and completeness of gene content was measured using Benchmarking Universal Single-Copy Orthologs (BUSCO). Draft assemblies with high duplications were processed using Purge Haplotigs and Purge Dups to lessen duplications with minimal impact on genome completeness. De novo assemblies of Huani, Paho and 'Carabao' were then generated with primary contig sizes of 463.64 Mb, 508.95 Mb and 401.51 Mb respectively. These draft assemblies of Huani, Paho and 'Carabao' showed 96.90%, 95.17% and 99.07% complete BUSCOs respectively which is comparable to 'Tommy Atkins' genome (98.6%). Using two mango transcriptome data (pooled RNA-seq from different mango varieties and tissues), 91-96% or 24-30 million reads were successfully mapped back for each generated assembly indicating high degree of completeness. The results obtained demonstrated the highly contiguous, phased, and near complete genome assembly of three Philippine mango species for structural and functional annotation of gene units, especially those with economic importance.

• Journal of the Korean Institute of Gas
• /
• v.27 no.3
• /
• pp.91-97
• /
• 2023

Aging construction machinery and vehicles with old diesel engines usually have a long life span, so they continue to emit harmful emissions. Therefore, replacing these older diesel engines with engines that meet the latest emisstion standard is expected to help improve air quality, and engines with propane fuels, which are easily available at construction sites, can be an appropriate alternative. In this study, a propane fueled engine was developed based on a 6.8-liter CNG engine, and technologies such as gas injectors, exhaust gas recirculation (EGR), and enhanced catalysts were applied. As a result, nitrogen oxides achieved half of the emission performance at the Stage-V level, the latest emission standard, while securing diesel engine output and torque in the same class.

• Korean Journal of Remote Sensing
• /
• v.39 no.5_4
• /
• pp.1145-1153
• /
• 2023

Urban trees play an important role in absorbing carbon dioxide from the atmosphere, improving air quality, mitigating the urban heat island effect, and providing ecosystem services. To effectively manage and conserve urban trees, accurate spatial information on their location, condition, species, and population is needed. In this study, we propose an algorithm that uses a high-resolution urban tree cover map constructed from deep learning approach to separate trees from the urban land surface and accurately detect tree locations through local maximum filtering. Instead of using a uniform filter size, we improved the tree detection performance by selecting the appropriate filter size according to the tree height in consideration of various urban growth environments. The research output, the location and height of individual trees in human settlement over Suwon, will serve as a basis for sustainable management of urban ecosystems and carbon reduction measures.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.5
• /
• pp.131-138
• /
• 2023

In this paper, a free space optical communication device that can be used in a mobile base station of several km or less was fabricated and its characteristics were investigated. To overcome the loss due to atmospheric transmission, an optical fiber amplifier (EDFA) with an output of 23 dBm or more was used. In order to increase the focusing speed and miniaturization of the laser beam, an optical lens was manufactured, and a transmission lens was designed to have beam divergence within the range of 1.5 to 1.8 [mrad]. A PT module that controls PAN/TILT was fabricated in order to reduce pointing errors and effective automatic alignment between transceiver devices. In this study, Reed-Solomon (RS) code was used to maintain the transmission quality above a certain level. It was manufactured to be able to communicate at a wireless distance of 300m in a weather situation with visibility of 300m. For performance measurement, it was measured using BERT and eye pattern analyzer, and it was confirmed that BER can be maintained at 2.5Gbps.

• International Journal of Internet, Broadcasting and Communication
• /
• v.16 no.2
• /
• pp.10-21
• /
• 2024

Recently, audio systems are changing the configuration of conventional sound reinforcement (SR) systems and public address (PA) systems by using audio over IP (AoIP), a technology that can transmit and receive audio signals based on internet protocol (IP). With the advancement of IP technology, AoIP technologies are leading the audio market and various technologies are being released. In particular, audio networks and control hierarchy over peer-to-peer (Anchor) technology based on AoIP is a system that transmits and receives audio signals over a wide bandwidth without an audio mixer, creating a novel paradigm for existing audio system configurations. Anchor technology forms an audio system by connecting audio sources and output equipment with On-site audio center (OAC), a device that can transmit and receive IP. Anchor's receiving OAC is capable of receiving and mixing audio signals transmitted from different IPs, making it possible to configure a novel audio system by replacing the conventional audio mixer. However, Anchor technology does not have the ability to provide audio effects to input devices such as microphones and instruments in the audio system configuration. Due to this, when individual control of each audio source is required, there is a problem of not being able to control the input signal, and it is impossible to individually affect a specific input signal. In this paper, we implemented a tone control module that can individually control the tone of the audio source of the input device using the audio processor core in the audio system based on Anchor technology, tone control for audio sources is possible through a tone control module connected to the transmitting OAC. As a result of the study, we confirmed that OAC receives the signal from the audio source, adjusts the tone and outputs it on the tone control module. Based on this, it was possible to solve problems that occurred in Anchor technology through transmitting OAC and tone control modules. In the future, we hope that the audio system configuration using Anchor technology will become established as the standard for audio equipment.

• Journal of IKEEE
• /
• v.28 no.3
• /
• pp.445-450
• /
• 2024

This paper presents a varactor-less voltage-controlled oscillator (VCO) at W-band (75-110 GHz) with a compact size in a 0.15-㎛ GaAs pHEMT technology. For varactor-less frequency tuning, an inductive tuning circuit is employed. An active inductor is realized by the common-gate stage with gate termination and shows a wide tuning range with a high quality factor (Q-factor) compared with the conventional varactor diode. Colpitts topology with source feedback is employed for the oscillation core of the VCO. The varactor-less VCO exhibits a measured tuning range of 5.8 % and peak output power of 5.7 dBm at 88 GHz while the 146 mW of dc power is dissipated. Due to compact layout design, the chip size is only 0.48 mm².

• Journal of Advanced Navigation Technology
• /
• v.28 no.5
• /
• pp.632-639
• /
• 2024

In this paper, the analysis method and results of audio data through LVDS interface and data Acquisition of the intercom. Intercom uses LVDS interface to transmit/receive digital audio data between audio interface unit and intercom control panel and to data acquisition of audio signals. Data acquisition using LVDS interface is essential for downloading various audio signals interfaced to the intercom to a PC and performing data analysis on noise, audio qualitys, etc. To achieve this, hardware for audio data acquisition was configured in the intercom test equipment. As a result, individual analysis of intercom input/output audio signals before and after logic processing was possible, which was effective in deriving the cause of noise signals. In addition, by data acquisition on actual voice communication and audio signals in ac system integrated laboratory and an environment/ electromagnetic test, audio signal level measurements and frequency analysis were performed to debug noise signal removal and verify the audio quality of the intercom.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.8A
• /
• pp.918-927
• /
• 2004

WCDMA system is 3rd generation wireless mobile system specified by 3GPP. In WCDMA downlink, two power control schemes are operated. One is inner loop power control operated in every slot. Another is outer loop power control based on one frame time. Base station (BS) can estimate proper transmission power by these two power control schemes. However, because each MS's transmission power makes a severe effect on BS's performance, BS cannot give excessive transmission power to the specific user. 3GPP defined Power Control Dynamic Range (PCDR) to guarantee proper BS's performance. In this paper, we propose Adaptive PCDR algorithm. By APCDR algorithm, Radio Network Controller (RNC) can estimate each MS's current state using received signal to interference ratio (SIR). APCDR algorithm changes MS's maximum code channel power based on frame. By proposed scheme, each MS can reduce wireless channel effect and endure outages in cell edge. Therefore, each MS can obtain better QoS. Simulation result indicate that APCDR algorithm show more attractive output than fixed PCDR algorithm.