LDPC 부호화된 멀티유저 상향링크 Massive-MIMO 시스템의 반복 검출 및 복호 수신기

박진수(Jin Soo Park),김인선(Inseon Kim),송홍엽(Hong-Yeop Song),한성우(Sung Woo Han) 한국통신학회 2014 韓國通信學會論文誌 Vol.39 No.9(통신이론)

본 논문에서는 LDPC 부호화된 멀티유저 상향링크 massive-MIMO 시스템에서, 연판정 MRC 검출기와 LDPC 복호기를 이용한 반복적 검출 및 복호 수신기를 제안한다. 우선 MRC 검출기에 대해 연판정 기법을 제안하고, 검출기와 LDPC 복호기간 정보 교환 관계를 유도한다. 제안된 반복적인 검출 및 복호 과정을 통해 성능이 향상될 수 있음을 시뮬레이션을 통해 확인한다. In this paper, we propose an iterative detection and decoding scheme for the LDPC coded multiuser uplink massive-MIMO systems. We consider the simple maximal ratio combining (MRC) detector and LDPC decoder. We formulate the soft output of MRC detector and the relation between the extrinsic informations of the detector and decoder. The performance improvement of the proposed iterative detection and decoding scheme is shown by computer simulation.

조분시멘트를 사용한 매스콘크리트의 열전달계수 변화에 따른 수화열 해석

김호수(Kim Ho-Soo),한승백(Han Seung-Baek),김호룡(Kim Ho-Ryong) 대한건축학회 2009 大韓建築學會論文集 : 構造系 Vol.25 No.5

The several methods to evaluate the harmful temperature crack according to the hydration heat of mass concrete are required as the buildings become massive. This study considers the various variables to influence the occurrence of hydration heat in the hydration heat analysis. First, some different heat transfer coefficients according to curing conditions are applied in the analysis process to evaluate the hydration heat difference of the internal and external parts of mass concrete. Also, the occurrence effect of hydration heat by the use of coarse particle cement is verified through the comparison with ordinary portland cement. Specifically, the thermal stress and temperature crack coefficients are analyzed for the effective evaluation of hydration heat analysis results.

대량 흉수의 원인과 성상-국내 한 대학병원의 경험

박송리 ( Song Ree Park ),김지현 ( Jee Hyun Kim ),하나래 ( Na Rae Ha ),이재형 ( Jae Hyung Lee ),김상헌 ( Sang Heon Kim ),손장원 ( Jang Won Sohn ),윤호주 ( Ho Joo Yoon ),신동호 ( Dong Ho Shin ),박성수 ( Sung Soo Park ),김태형 ( Tae 대한결핵 및 호흡기학회 2006 Tuberculosis and Respiratory Diseases Vol.61 No.5

연구배경: 대량 흉수의 가장 흔한 원인은 악성으로 알려졌으나 이에 대한 보고가 많지 않고, 지역 및 시대에 따라 다른 분포를 보였다. 저자들은 결핵의 유병율이 높은 국내에서 대량 흉수의 원인 질환의 분포를 알아보고, 원인 질환 감별을 위한 흉수의 분석지표에 대해 알아보기 위해 연구를 시행하였다. 방법: 2002년 7월부터 2005년 7월까지 한양대학교 구리병원에 입원하여 흉수 천자를 시행하였던 298명 환자를 대상으로 후향적 조사를 시행하였다. 대량흉수는 흉부단순촬영에서 일측 흉곽의 2/3 이상을 차지한 경우로 정의하였고 각 환자에서 혈청 생화학 검사, 흉수 천자 소견을 비교하였다. 결과: 전체 298명의 흉수 예 중 대량 흉수는 41예, 13.8% 이었다. 대량 흉수의 원인으로는 악성 흉수가 19예 (46.3%)로 가장 많았고 결핵 15예 (36.6%), 부폐렴성 흉막염 및 농흉 4예(9.8%), 여출성 흉수 3예(7.3%) 순이었다. 대량 흉수 중 악성 흉수 (n=19)와 양성 흉수군 (n=22)의 비교 시 악성 흉수에서 ADA가 낮고(30.5 vs 86.2;p=0.017), amylase 수치가 높았다 (349.0 vs 39.2;p=0.031). 흉수 적혈구는 악성 흉수 군에서 높은 경향을 보였다(95,406 vs 22,105;p=0.052). 결론: 국내에서 대량 흉수의 원인으로는 악성 외에도 결핵에 의한 경우가 많았으며, ADA가 낮은 혈성 흉수는 악성을, ADA가 높은 림프구성 흉수는 결핵의 가능성을 고려해 볼 수 있겠다. Background: Differential diagnosis is very important in patients with pleural effusions. A few studies on the etiologies of massive pleural effusions have been reported, but these were conducted in different decades and locations. In the present study, the etiologic spectrum of massive pleural effusions in Korea, were evaluated through an investigation at one university hospital. Methods: Retrospective chart reviews were performed in patients having undergone thoracentesis between July 2002 and July 2005. Pleural effusions were deemed to be massive if they occurred in two thirds or more of one hemithorax. The etiologies of massive pleural effusions, pleural fluid findings, serum laboratory findings, and sputum and pleural fluid cytologies were compared. Results: Of 298 pleural effusions cases, 41 (13.8%) had massive pleural effusions. The most frequent causes of massive pleural effusions were malignancy (19; 46.3%) followed by tuberculosis (15; 36.6%), parapneumonic effusion (4; 9.8%) and transudate (3; 7.3%). Compared with massive benign effusions, patients with massive malignant pleural effusions were more likely to have lower adenosine deaminase (ADA) activity, a higher amylase level and higher RBC count in their pleural fluids. Also, compared with non-tuberculosis effusions, patients with massive tuberculous pleural effusions were more likely to have lower RBC and neutrophil counts, but a higher lymphocyte count, adenosine deaminase (ADA) activity and protein level. Conclusion: The most common etiologies of massive pleural effusions in Korea are malignancy and tuberculosis. A high ADA content favors a tuberculous condition, while bloody effusions with a relatively lower ADA content. Favors malignancy. The proportion of tuberculosis in massive pleural effusions was higher than in previous reports. (Tuberc Respir Dis 2006; 61: 456-462)

Performance Analysis of MRT-Based Dual-Polarized Massive MIMO System with Space-Polarization Division Multiple Access

( Jun-ki Hong ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.8

In recent years, one of the most remarkable 5G technologies is massive multiple-input and multiple-output (MIMO) system which increases spectral efficiency by deploying a large number of transmit-antennas (eg. tens or hundreds transmit-antennas) at base station (BS). However, conventional massive MIMO system using single-polarized (SP) transmit-antennas increases the size of the transmit-array proportionally as the number of transmit-antennas increases. Hence, size reduction of large-scale transmit-array is one of the major concerns of massive MIMO system. To reduce the size of the transmit-array at BS, dual-polarized (DP) transmit-antenna can be the solution to halve the size of the transmit-array since one collocated DP transmit-antenna deploys vertical and horizontal transmit-antennas compared to SP transmit-antennas. Moreover, proposed DP massive MIMO system increases the spectral efficiency by not only in the space domain but also in the polarization domain whereas the conventional SP massive MIMO system increases the spectral efficiency by space domain only. In this paper, the comparative performance of DP and SP massive MIMO systems is analyzed by space division multiple access (SDMA) and space-polarization division multiple access (SPDMA) respectively. To analyze the performance of DP and SP massive MIMO systems, DP and SP spatial channel models (SCMs) are proposed which consider depolarized propagation channels between transmitter and receiver. The simulation results show that the performance of proposed 32 transmitter (Tx) DP massive MIMO system improves the spectral efficiency by about 91% for a large number of user equipments (UEs) compare to 32Tx SP massive MIMO system for identical size of the transmit-array.

소아 환자에서의 대량수혈 프로토콜

이환태,박필환,서일혜,안정열,서자영,정지훈,김문진,이정남,이길재,김경희 대한진단검사의학회 2016 Laboratory Medicine Online Vol.6 No.2

The number of massive transfusions for pediatric patients has risen owing to the increasing number of complex surgeries and trauma centers. However, as there are only a few studies on pediatric massive transfusion, adult massive transfusion protocols are used for pediatric patients in many hospitals and institutions. Although massive transfusion protocols would improve the outcomes and reduce the received blood products during transfusion, pediatric patients differ from adults in the tolerability to transfusion, incidence of coagulopathy, and mechanisms of injuries. Therefore clinical physicians have requested for a pediatric massive transfusion protocol. Herein, we reviewed pediatric massive transfusion protocols that have been used in various clinical settings. To date, only a few single-center studies with a small number of pediatric patients have been performed. Even though these studies did not show improvement in outcomes such as mortality and side effects, they reported a short preparation time for fresh frozen plasma products and a low coagulopathy rate in pediatric massive transfusion groups. Therefore, large, prospective, multicenter studies are needed to identify the empiric ratio of blood products for improving outcomes of pediatric patients who need massive transfusion. 최근 외상센터의 증가와 이식 수술과 같은 복잡한 수술이 증가하면서 소아에서도 대량수혈을 필요로 하는 경우가 많아지고 있다. 성인에서와 달리 아직 소아 환자에서 대량수혈에 대한 연구는 미흡한 실정이며, 많은 병원과 기관에서는 성인 대량수혈 프로토콜을 소아 환자에도 적용하고 있다. 이러한 프로토콜은 환자의 생존율을 높이고 수혈 시 사용되는 혈액제제의 양도 줄일 수 있다는 장점이 있으나, 소아 환자의 경우 응고병증에 대한 내성이나 수상 기전이 성인과 다르다. 이러한 이유로 임상의사들의 소아 대량수혈 프로토콜에 대한 요구가 있어, 현재 사용되고 있는 프로토콜에 관한 국내외 문헌을 고찰해 보았다. 지금까지 발표된 소아 대량수혈 프로토콜 관련 연구들은 모두 단일 기관에서 적은 수의 환자를 대상으로 진행되었으며, 대조군에 비해 유의하게 높은 생존율 을 보이지는 않았으나 소아 대량수혈 프로토콜에 따라 처치받은 환자군에서 짧은 신선동결혈장 준비 시간과 낮은 응고병증 발생빈도를 보였다. 따라서 국내에서도 여러 기관이 포함된 대규모 연구를 통해서 대량수혈을 필요로 하는 소아 환자의 생존율을 높일 수 있는 최적화된 혈액제제 비율과 대량수혈 프로토콜을 구축할 필요가 있을 것으로 사료된다.

Analysis of Massive Transfusion for Trauma Patients and Non-Trauma Patients in a Tertiary Hospital

김혜림,유동원,신경화,이현지,김형회 대한수혈학회 2016 大韓輸血學會誌 Vol.27 No.3

Background: Management of patients with massive hemorrhage often requires the massive blood transfusions. However, few studies have investigated the effects of massive transfusions on non-traumatic patients. Therefore, this study analyzed mortality and descriptive data for patients receiving massive transfusion, including non-trauma patients and trauma patients. Methods: We reviewed a retrospective audit of massive transfusions to investigate the major causes, patient characteristics, ratio of the blood components, and the mortality of massively transfused patients. The analysis was performed using electronic medical records collected from January 2010 to December 2013. Patients who had received a massive transfusion (≥10 units of RBCs within 24-hours) were categorized into trauma and non-trauma patients. We calculated the ratio of blood components and investigated the relationship between ratio and mortality. Descriptive statistics were used to characterize the patients and the indications. Results: A total of 532 massive transfusions were performed, including 187 trauma and 345 non-trauma patients. The overall mortality rate was 32.0%, encompassing 36.4% of the trauma patients and 29.6% of the non-trauma patients. The mortality in trauma patients was significantly reduced (P<0.001) within the first 48-hours compared with that in non-trauma patients, which was due to the high FFP: RBC ratio transfusion. The annual FFP: RBC ratio in trauma patients showed an increasing trend. Non-trauma patients showed no relationship between mortality and procedure indication/blood component ratio. Conclusion: We report clinical data pertaining to massive transfusions. Annual increasing FFP: RBC ratio in trauma patients was associated with a decreasing mortality. Non-trauma patients showed heterogeneous characteristics and a lower FFP: RBC ratio than trauma patients.

Efficacy of Bakri Balloon Tamponade in Massive Postpartum Hemorrhage: A Series of 57 Cases

( Ha Yan Kwon ),( Young-han Kim ),( Yong-won Park ),( Ja-young Kwon ) 대한주산의학회 2016 大韓周産醫學會雜誌 Vol.27 No.4

Purpose: To evaluate the efficacy of intrauterine Bakri balloon tamponade as a management of massive postpartum hemorrhage (PPH). Methods: Retrospective study including women who underwent intrauterine Bakri balloon tamponade for massive PPH between April 2010 and July 2015 was conducted. Massive PPH was defined as estimated blood loss exceeding 1,500 mL. Bakri balloon was inserted into uterus if women had PPH despite medical treatment after vaginal delivery or cesarean section. The balloon was inflated with sterile saline and removed after 12-24 hours. Failure was defined as needing another procedure for hemorrhage control. Demographic, obstetric and specific factors in regard to the Bakri balloon use were recorded. The successful rate of hemostasis by Bakri balloon was evaluated. Results: Among 138 women with PPH managed Bakri balloon insertion, 57 patients were diagnosed with massive PPH. The most common cause of massive PPH was placenta previa without accreta (54.4%), uterine atony (33.3%), placenta previa with accreta (10.5%) and placenta accreta (1.8%). The mean estimated blood loss was 2279.0 mL (range, 1,500-6,500 mL). The rate of successful control of massive PPH after Bakri balloon placement was 82.5%. From the cases of 57 patients, 10 patients needed additional procedures; five required uterine artery embolization and five underwent cesarean hysterectomy. No short-term complications or maternal death were observed after Bakri balloon insertion. Conclusion: Bakri balloon tamponade is an effective, simple and quick approach in the treatment of massive PPH and it is useful as complementary management for earning time for another procedure.

Clinical Observation Study of Massive Blood Transfusion in a Tertiary Care Hospital in Korea

Seoyoung Yoon,Ae Ja Park,김현옥 연세대학교의과대학 2011 Yonsei medical journal Vol.52 No.3

Purpose: Massive blood transfusios are uncommon. The goal of this study was to propose an ideal ratio for the blood component of massive hemorrhage treatment after review of five years of massive transfusion practice, in order to have the best possible clinical outcomes. Materials and Methods: We defined a ‘massive transfusionʼ as receiving 10 or more units of red blood cells in one day. A list of patients receiving a massive transfusion from 2004 to 2008 was generated using the electronic medical records. For each case, we calculated the ratio of blood components and examined its relationship to their survival. Results: Three hundred thirty four patients underwent massive transfusion during the five years of the study. The overall seven-day hospital mortality for massive transfusion patients was 26.1%. Factors independently predictive of survival were a fresh-frozen plasma (FFP)/packed red blood cell (pRBC) ratio≥1.1 with an odds ratio (OR) of 1.96 (1.03-3.70), and elective admission with an OR of 2.6 (1.52-4.40). The receiver operation characteristic (ROC) curve suggest that a 1 : 1 : 1 ratio of pRBCs to FFP to platelets is the best ratio for survival. Conclusion: Fixing blood-component ratios during active hemorrhage shows improved outcomes. Thus, the hospital blood bank and physician hypothesized that a fixed blood component ratio would help to reduce mortality and decrease utilization of the overall blood component.

외상성 응고장애와 대량수혈

이대상 대한수혈학회 2020 大韓輸血學會誌 Vol.31 No.2

A massive blood transfusion is a challenging situation that can be encountered in the treatment of trauma patients. Under these circumstances, clinicians should conduct appropriate blood transfusions using the massive transfusion protocol, and make efforts to prepare and apply these protocols to the systems of each hospital in advance. In addition, the effect of massive bleeding on the body highlights the need to understand why fresh frozen plasma and platelets, as well as packed red blood cells (pRBC), are needed during massive transfusion. In hemorrhagic patients, blood pressure maintenance through transfusion is an important part, but above all, efforts to control sustained bleeding by controlling and treating the bleeding itself are more important. This is because patients need to recover their organs after early resuscitation by minimizing the side effects of transfusion. No research has been done to compare the restrictive transfusion and liberal transfusion strategies in patients requiring massive transfusion. On the other hand, various studies suggest that it is more advantageous to apply a liberal blood transfusion strategy in patients with severe or older age. Nevertheless, there has been insufficient research to apply it generally. Therefore, for patients whose resuscitation has been performed by applying a massive transfusion protocol, a reasonable treatment approach would be to shift to a strategy to supplement poor coagulation factors through a goal-directed transfusion. (Korean J Blood Transfus 2020;31:101-108)

일개 3차 병원에서 외상 환자에 대한 응급실과 기존 응급실의 대량수혈 비교 분석 연구

유동원,김혜림,신경화,이현지,장철훈,김형회 대한수혈학회 2017 大韓輸血學會誌 Vol.28 No.3

Background: Massive transfusion is defined as an 8- to 10-unit transfusion of red blood cells (RBC) within 24 hours in an adult or a 4- to 5-unit transfusion of RBC within 1 hour. Massive transfusion plays an important role in saving the lives of trauma patients. We investigated changes in blood volume and blood product ratios used in massive transfusion in trauma patients at emergency room (ER) and traumatic center emergency room (TER) and evaluated prognostic factors of patients based on mortality. Methods: We compared massive transfusion requirements for trauma patients between the ER and TER such as amount of transfusion, mortality, and ratio of products. The patients selected were over 18 years old. The patients who were transfused with more than 10 units of RBC within 24 hours were defined as massive transfusion patients. Results: There were a total of 189 people who received massive transfusions at the ER over 4 years, and 67 patients were transfused at the TER over 1 year. There was no significant difference in the ratio of blood products between the two groups, but the mortality rate of the ER (63.1%) was significantly higher than the TER (41.8%). Conclusion: The ratio of blood products was not related to patient mortality, but the mortality rate of the TER was lower than that of the ER.