• 대한영상의학회지
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• 제85권4호
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• pp.789-794
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• 2024

본 증례 보고에서는 가속화된 진행성거대섬유증으로 오인된 카플란 증후군을 소개한다. 환자는 15년 전 탄광부진폐증을 진단받고 20년 이상 류마티스관절염 치료를 받은 자로 연속적인 CT 검사에서 진행거대섬유증의 진행과 함께 폐기저부에 동공을 동반한 다발성 폐결절이 관찰되었다. CT상 가속화된 진행성거대섬유증 소견으로 오인할 수 있는 카플란 증후군 증례를 보고하고자 한다.

• 한국통신학회논문지
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• 제41권11호
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• pp.1630-1638
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• 2016

본 논문에서는 다중 사용자(multiuser)가 다수의 기지국 안테나(MIMO, Multiple-Input and Multiple-Output)를 동시에 사용하는 다중 사용자 massive MIMO 시스템 환경을 고려한다. 다중 사용자를 동시에 지원하기 위해 기지국에서는 ZFBF(Zero-Forcing Beamforming) 기법을 고려하고 수신 신호 검출을 위해 파일럿 신호를 고려한 하향 링크 프레임 구조를 적용하여 평균 셀 용량을 도출한다. 평균 셀 용량은 기지국 안테나 수 및 사용자 수에 대해 오목 함수 (concave function)임을 수식적으로 증명하고, 오목 함수 특징을 통해 최적의 기지국 안테나 수 및 사용자 수를 도출한다. 실험 결과를 통해 수식적으로 도출한 최적 값을 검증하고, 최적값 기반의 평균 셀 용량은 송신 SNR(Signal to Noise Ratio)에 비례하여 증가함을 확인할 수 있다.

• Clinics in Shoulder and Elbow
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• 제13권1호
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• pp.132-140
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• 2010

목적: 광범위 회전근 개 파열에 대한 수술적 치료는 매우 어려우며, 다양한 수술 방법이 알려져 있다. 여러 수술 방법 중 광범위 회전근 개 파열에서 적용될 수 있는 관절 성형술에 대해 고찰하고자 한다. 대상 및 방법: 광범위 회전근 개 파열에 대한 수술 방법 중 하나인 관절 성형술에 관한 문헌들을 조사하여 요약하고 정리하였다. 결과: 봉합이 불가능한 광범위 회전근 개 파열 환자에서 관절 성형술은 일차적 치료법 또는 구제술로 사용될 수 있으며, 반관절 성형술은 오구 견봉 궁이 건재할 경우 Neer의 제한적 기준을 목표로 삼는다면 만족스런 결과를 얻을 수 있다. 또한, 역형 견관절 전 성형술은 가성 마비를 동반한 고령의 환자에서 동통 완화와 능동적 거상을 회복할 수 있는 구제술이다. 결론: 치료가 어려운 광범위 회전근 개 파열 환자에서 적절한 관절 성형술의 선택은 견관절의 동통 완화와 기능적 관절 운동 범위 회복을 가능케 할 수 있을 것으로 사료된다.

• Tuberculosis and Respiratory Diseases
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• 제47권2호
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• pp.255-258
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• 1999

Pneumoconiosis, very popular to coal miners who are exposed to coal dusts dominantly, was introduced in the 19th century to describe lung diseases consequent to the inhalation of mineral dusts. Coal workers' pneumoconiosis(CWP) colloquially called "black lung" in the United States, is a distinct pathologic entity resulting from the tissue reaction to deposits of dust include the coal macule, which associated with focal emphysema constitutes the characteristic lesion of simple CWP and complicated CWP or progressive massive fibrosis(PMF). Coal mining are also associated with chronic bronchitis, chronic airflow limitation, and/or generalized emphysema. Progressive massive fibrosis lesions may imprint on and obliterate airways and vessels, and cavitation is not uncommon, being the consequence of ischemic necrosis or mycobacterial infections. We report a case which is unusual form of progressive massive fibrosis to be differentiated from lung carcinoma. It is a rapid growing PMF with ischemic necrosis. By the studies which are about risk of having progressive massive fibroois, it is predicted to be 1.4%. And the other study shows that simple pneumoconiosis clearly predisposed to PMF, with five year attack rates of 13.9%, 12.5%, 4.4% and 0.2% among men with categories 3, 2, 1, and 0 respectively at the start of the risk periods.

• 천문학회지
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• 제48권1호
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• pp.21-55
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• 2015

If the Universe is dominated by cold dark matter and dark energy as in the currently popular ${\Lambda}CDM$ cosmology, it is expected that large scale structures form gradually, with galaxy clusters of mass $M{\geq}10^{14}M_{\odot}$ appearing at around 6 Gyrs after the Big Bang (z ~ 1). Here, we report the discovery of 59 massive structures of galaxies with masses greater than a few times $10^{13}M_{\odot}$ at redshifts between z = 0.6 and 4.5 in the Great Observatories Origins Deep Survey fields. The massive structures are identified by running top-hat filters on the two dimensional spatial distribution of magnitude-limited samples of galaxies using a combination of spectroscopic and photometric redshifts. We analyze the Millennium simulation data in a similar way to the analysis of the observational data in order to test the ${\Lambda}CDM$ cosmology. We find that there are too many massive structures (M > $7{\times}10^{13}M_{\odot}$) observed at z > 2 in comparison with the simulation predictions by a factor of a few, giving a probability of < 1/2500 of the observed data being consistent with the simulation. Our result suggests that massive structures have emerged early, but the reason for the discrepancy with the simulation is unclear. It could be due to the limitation of the simulation such as the lack of key, unrecognized ingredients (strong non-Gaussianity or other baryonic physics), or simply a difficulty in the halo mass estimation from observation, or a fundamental problem of the ${\Lambda}CDM$ cosmology. On the other hand, the over-abundance of massive structures at high redshifts does not favor heavy neutrino mass of ~ 0.3 eV or larger, as heavy neutrinos make the discrepancy between the observation and the simulation more pronounced by a factor of 3 or more.

• Clinics in Shoulder and Elbow
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• 제9권1호
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• pp.20-26
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• 2006

Purpose: To evaluate the usefulness and functional results of open repair of massive rotator cuff tears combined with or without the tenoplasty of biceps long head. Materials and Methods: From March 2003 to August 2004, we evaluated 18 cases of the patient treated with open repair of massive rotator cuff tears. The mean age was 56 years and mean follow-up period was 15 months. We performed open repair of massive rotator cuff tears by tendon to bone repair, but in irrepairable 4 cases for tendon to bone repair performed open repair combined with tenoplasty of biceps long head. The functional results were assessed using the Constant score, the parameters of which were pain, dialy activity, mobility, strength and satisfaction. Results: The functional results were excellent in 4 cases, good in 8 cases, fair in 3 cases and poor in 3 cases. And the results of open repair combined with tenoplasty of biceps long head were good in 2 cases and fair in 2 cases. Re-repair was done in 1 case for re-rupture. And the functional result of this case was fair. The 3 poor cases were suspected re-rupture, the factor of which old age and weakened rotator cuff. It was impossible to do re-repair. Conclusion: The open repair combined with or without tenoplasty of biceps long head is a useful and effective method for massive rotator cuff tear.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권8호
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• pp.2797-2820
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• 2015

In order to accommodate huge number of antennas in a limited antenna size, a large scale antenna array is expected to have a three dimensional (3D) array structure. By using the Active Antenna Systems (AAS), the weights of the antenna elements arranged vertically could be configured adaptively. Then, a degree of freedom (DOF) in the vertical plane is provided for system design. So the three-dimension MIMO (3D MIMO) could be realized to solve the actual implementation problem of the massive MIMO. However, in 3D massive MIMO systems, the pilot contamination problem studied in 2D massive MIMO systems and the inter-cell interference as well as inter-vertical sector interference in 3D MIMO systems with vertical sectorization exist simultaneously, when the number of antenna is not large enough. This paper investigates the interference management towards the above challenges in 3D massive MIMO systems. Here, vertical sectorization based on vertical beamforming is included in the concerned systems. Firstly, a cooperative joint vertical beams adjustment and pilot assignment scheme is developed to improve the channel estimation precision of the uplink with pilots being reused across the vertical sectors. Secondly, a downlink interference coordination scheme by jointly controlling weight vectors and power of vertical beams is proposed, where the estimated channel state information is used in the optimization modelling, and the performance loss induced by pilot contamination could be compensated in some degree. Simulation results show that the proposed joint optimization algorithm with controllable vertical beams' weight vectors outperforms the method combining downtilts adjustment and power allocation.

• Tuberculosis and Respiratory Diseases
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• 제63권5호
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• pp.430-434
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• 2007

저자들은 71세 여자환자가 대량객혈을 주소로 내원하여 폐동맥과 기관지의 누공을 확인한 증례를 경험하였기에 문헌고찰과 함께 보고하는 바이다.

• Journal of Communications and Networks
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• 제15권4호
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• pp.383-397
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• 2013

In this paper, the sensitivity of massive antenna arrays and digital beamforming to radio frequency (RF) chain in-phase quadrature-phase (I/Q) imbalance is studied and analyzed. The analysis shows that massive antenna arrays are increasingly sensitive to such RF chain imperfections, corrupting heavily the radiation pattern and beamforming capabilities. Motivated by this, novel RF-aware digital beamforming methods are then developed for automatically suppressing the unwanted effects of the RF I/Q imbalance without separate calibration loops in all individual receiver branches. More specifically, the paper covers closed-form analysis for signal processing properties as well as the associated radiation and beamforming properties of massive antenna arrays under both systematic and random RF I/Q imbalances. All analysis and derivations in this paper assume ideal signals to be circular. The well-known minimum variance distortionless response (MVDR) beamformer and a widely-linear (WL) extension of it, called WL-MVDR, are analyzed in detail from the RF imperfection perspective, in terms of interference attenuation and beamsteering. The optimum RF-aware WL-MVDR beamforming solution is formulated and shown to efficiently suppress the RF imperfections. Based on the obtained results, the developed solutions and in particular the RF-aware WL-MVDR method can provide efficient beamsteering and interference suppressing characteristics, despite of the imperfections in the RF circuits. This is seen critical especially in the massive antenna array context where the cost-efficiency of individual RF chains is emphasized.

• 천문학회보
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• 제37권2호
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• pp.73.2-73.2
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• 2012

Matusoka & Kawara (2010) showed that the number density of the most massive galaxies (log $M/M_{\odot}=11.5-12.0$) increases faster than that of the next massive group (log $M/M_{\odot}=11.0-11.5$) during 0 < z < 1. This appears to be in contradiction to another important empirical concept of "downsizing". We attempt to understand the two observational findings in the context of the hierarchical merger paradigm using semi-analytic techniques. Our models closely reproduce the result of Matusoka & Kawara (2010). Downsizing can also be understood as larger galaxies have on average smaller assembly ages but larger stellar ages. Our fiducial models further reveal the details on the history of stellar mass growth of massive galaxies. The most massive galaxies (log $M/M_{\odot}=11.5-12.0$ at z=0), which are mostly brightest cluster galaxies, obtain roughly 70% of their stellar components via merger accretion. The role of merger accretion monotonically declines with galaxy mass: 45% for log $M/M_{\odot}=11.0-11.5$ and 20% for log $M/M_{\odot}=10.5-11.0$ at z = 0. The specific accreted stellar mass rates via galaxy mergers decline very slowly during the whole redshift range, while the specific star formation rates sharply decrease with time. In the case of the most massive galaxies, merger accretion becomes the most important channel for the stellar mass growth at z ~ 2. On the other hand, in-situ star formation is always the dominant channel in the $L_*$ galaxies.