Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Ann Dermatol ; 35(Suppl 1): S176-S177, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37853904
2.
Sensors (Basel) ; 22(23)2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36502117

RESUMO

In this paper, we propose a novel interference alignment (IA) technique for an in-band full-duplex (IBFD) multiple-input multiple-output (MIMO) cellular network where a base station (BS) and user equipment (UE) are equipped with multiple antennas, and the local channel state information (CSI) is available at all nodes. Considering a practical IBFD MIMO cellular network, it is assumed that only the BS operates with full-duplex (FD) communication while UE operate in half-duplex (HD) mode. These IBFD networks introduce a new type of interference called cross-link interference (CLI), in which uplink UE affects downlink UE. The proposed IA technique consists of two symmetric IA schemes according to the number of antennas in the uplink and downlink UE, and both schemes effectively mitigate CLI in the IBFD MIMO network. It is worth noting that both IA schemes are adaptively applicable according to the network's quality-of-service (QoS) requirements, such as uplink and downlink traffic demands. Furthermore, we theoretically characterize and prove the achievable sum-degrees-of-freedom (DoF) of the proposed IA technique. Simulation results show that the proposed IA technique significantly improves the sum rate performance compared to conventional HD communications (multi-user MIMO) while achieving the same achievable DoF as the interference-free IBFD MIMO network.


Assuntos
Comunicação , Simulação por Computador
3.
Sensors (Basel) ; 22(20)2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36298404

RESUMO

In this paper, we revisit a two-user space-time line coded uplink non-orthogonal multiple access (STLC-NOMA) system for Internet-of-things (IoT) networks and propose a novel low-complexity STLC-NOMA system. The basic idea is that both IoT devices (stations: STAs) employ amplitude-shift keying (ASK) modulators and align their modulated symbols to in-phase and quadrature axes, respectively, before the STLC encoding. The phase distortion caused by wireless channels becomes compensated at the receiver side with the STLC, and thus each STA's signals are still aligned on their axes at the access point (AP) in the proposed uplink STLC-NOMA system. Then, the AP can decode the signals transmitted from STAs via a single-user maximum-likelihood (ML) detector with low-complexity, while the conventional uplink STLC-NOMA system exploits a multi-user joint ML detector with relatively high-complexity. We mathematically analyze the exact BER performance of the proposed uplink STLC-NOMA system. Furthermore, we propose a novel expectation-maximization (EM)-based blind energy estimation (BEE) algorithm to jointly estimate both transmit power and effective channel gain of each STA without the help of pilot signals at the AP. Somewhat interestingly, the proposed BEE algorithm works well even in short-packet transmission scenarios. It is worth noting that the proposed uplink STLC-NOMA architecture outperforms the conventional STLC-NOMA technique in terms of bit-error-rate (BER), especially with high-order modulation schemes, even though it requires lower computation complexity than the conventional technique at the receiver.

5.
Intest Res ; 19(1): 62-70, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32375208

RESUMO

BACKGROUND/AIMS: Neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) can serve as biomarkers for diagnosing and assessing disease activity in ulcerative colitis (UC). We investigated their clinical significance in UC. METHODS: We analyzed 48 patients with UC who underwent measurement of fecal calprotectin (FC) and endoscopy and 96 age- and sex-matched healthy controls. NLR and PLR were compared between the patients and healthy controls. The endoscopic activity was divided into 2 groups: group 1 (mild to moderate inflammation) and group 2 (severe inflammation) according to the Mayo endoscopic subscore in UC. RESULTS: To diagnose UC, the optimal cutoff of NLR and PLR was 2.26 (sensitivity 54.2%; specificity 90.6%; positive likelihood ratio 5.778, 95% confidence interval [CI] 2.944-11.339; area under the curve [AUC] 0.774, 95% CI, 0.690-0.859) and 179.8 (sensitivity 35.4%; specificity 90.6%; positive likelihood ratio 3.778, 95% CI 1.821-7.838; AUC 0.654, 95% CI 0.556-0.753), respectively. The optimal cutoff to differentiate group 1 and group 2 was 3.44, 175.9, and 453 µg/g for NLR, PLR, and FC, respectively (sensitivity, 63.6% vs. 90.9% vs. 81.8%; specificity, 81.1% vs. 78.4% vs. 73.0%; positive likelihood ratio, 3.364 vs. 4.205 vs. 3.027; AUC, 0.714 vs. 0.897 vs. 0.813). PLR had the highest AUC and positive likelihood ratio. CONCLUSIONS: NLR and PLR help differentiate patients with UC from healthy controls. NLR, PLR, and FC indicate endoscopic activity and may reflect intestinal mucosal conditions.

6.
Sensors (Basel) ; 20(22)2020 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-33198214

RESUMO

In this paper, a novel beamforming technique is proposed as the over-the-air computation (AirComp) framework in a multiple-input multiple-output (MIMO) Internet-of-things (IoT) network consisting of multiple IoT sensors (STAs) and a single access point (AP). We assume that each IoT device has the channel state information (CSI) from itself to the AP and the AP has the global CSI of all IoT devices. We consider the mean squared error (MSE), which represents the reliability of function computation, as a performance metric. In short, each IoT device exploits maximum-ratio transmission (MRT) as a transmit beamforming technique to improve MSE performance by taking full advantage of multiple transmit antennae. Moreover, for the receive beamforming, we first consider a receive antenna selection (RAS) technique as the simplest beamforming method at the AP. Then, a semi-definite relaxation (SDR) method and a successive convex approximation (SCA) algorithm are considered and compared with each other in terms of MSE. Finally, we propose a novel two-step beamforming algorithm to further improve the MSE performance of the aforementioned techniques. We have numerically verified through computer simulations that the proposed framework has an improved MSE performance of about 6dB compared to the conventional single-input multiple-output (SIMO) AirComp, even with only two transmit antennae, and the modified MRT outperforms the other transmit beamforming techniques. Furthermore, the proposed receive beamforming technique, a two-step algorithm, shows the best performance in terms of MSE compared to prior studies.

7.
Case Rep Gastroenterol ; 11(3): 559-563, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29033778

RESUMO

Basaloid squamous cell carcinoma of the esophagus is very rare. Further, polypoid type of esophageal cancer is also rare. We have recently treated a case of basaloid squamous cell carcinoma which presented as a 1.3-cm esophageal polyp. A 48-year-old woman was referred to our hospital because of a polypoid mass at 36 cm distance from the upper incisor on endoscopic examination, and the result of the biopsy was basaloid squamous cell carcinoma. The patient underwent Ivor Lewis operation with lymph node dissection. Two basaloid squamous cell carcinomas, of 1.3 and 0.4 cm, were diagnosed in the final pathologic examination. Regular periodic follow-up showed no evidence of recurrence or metastasis in the 5-month postoperative period.

8.
Am J Obstet Gynecol ; 198(1): 92.e1-6, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17905175

RESUMO

OBJECTIVE: The objective of the study was to analyze the characteristics of cervical cancer associated with pregnancy. STUDY DESIGN: Forty patients with cervical cancer associated with pregnancy were retrospectively identified between 1995-2003. Three controls for each case were matched on the basis of age, stage, histology, and date of treatment. RESULTS: Sampling of cervical cytology after the second trimester was the most common cause of delayed diagnosis. Among 12 patients who delayed treatment for fetal maturity, 2 died of disease. There was no difference in overall survival between pregnant and nonpregnant patients with stage Ib tumors. In contrast to nonpregnant patients, the depth of stromal invasion was not correlated with the incidence of lymph vascular space involvement and lymph node metastasis in pregnant patients. CONCLUSION: Thorough evaluation is warranted before deciding whether to delay treatment until fetal maturity. Pregnancy does not adversely affect the prognosis of early-stage cervical cancer significantly.


Assuntos
Complicações Neoplásicas na Gravidez/epidemiologia , Complicações Neoplásicas na Gravidez/patologia , Resultado da Gravidez , Neoplasias do Colo do Útero/epidemiologia , Neoplasias do Colo do Útero/patologia , Adulto , Distribuição por Idade , Estudos de Casos e Controles , Terapia Combinada , Comorbidade , Feminino , Idade Gestacional , Humanos , Incidência , Coreia (Geográfico)/epidemiologia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Cuidado Pós-Natal/métodos , Gravidez , Complicações Neoplásicas na Gravidez/terapia , Cuidado Pré-Natal/métodos , Probabilidade , Prognóstico , Valores de Referência , Estudos Retrospectivos , Medição de Risco , Estatísticas não Paramétricas , Análise de Sobrevida , Neoplasias do Colo do Útero/terapia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA