• Journal of Information Processing Systems
• /
• 제8권2호
• /
• pp.213-240
• /
• 2012

Safety critical systems, real time systems, and event-based systems have a complex set of events and their own interdependency, which makes them difficult to test ma Safety critic Safety critical systems, real time systems, and event-based systems have a complex set of events and their own interdependency, which makes them difficult to test manually. In order to cut down on costs, save time, and increase reliability, the model based testing approach is the best solution. Such an approach does not require applications or codes prior to generating test cases, so it leads to the early detection of faults, which helps in reducing the development time. Several model-based testing approaches have used different UML models but very few works have been reported to show the generation of test cases that use events. Test cases that use events are an apt choice for these types of systems. However, these works have considered events that happen at a user interface level in a system while other events that happen in a system are not considered. Such works have limited applications in testing the GUI of a system. In this paper, a novel model-based testing approach is presented using business events, state events, and control events that have been captured directly from requirement specifications. The proposed approach documents events in event templates and then builds an event-flow model and a fault model for a system. Test coverage criterion and an algorithm are designed using these models to generate event sequence based test scenarios and test cases. Unlike other event based approaches, our approach is able to detect the proposed faults in a system. A prototype tool is developed to automate and evaluate the applicability of the entire process. Results have shown that the proposed approach and supportive tool is able to successfully derive test scenarios and test cases from the requirement specifications of safety critical systems, real time systems, and event based systems.

• Journal of Forest and Environmental Science
• /
• 제33권4호
• /
• pp.342-347
• /
• 2017

Since the first report of the oak wilt disease at 2004 in Korea, the disease distributed over Korean peninsula and are still giving severe damages. The management of oak wilt disease in Korea has mainly focused on the control of insect vector, Platypus koryoensis. Neverthless the effective method for evaluating the pathogenicity of the pathogen, Raffaelea quercus-mongolicae (Rqm), and for screening chemical or biological agents with strong inhibitory activity against the pathogen, is absolutely necessary, an reliable method is not available so far. This study was conducted to develop the effective method for evaluating the pathogenicity of Rqm in oak trees. The culture suspensions of Rqm were artificially injected to the saplings of Quercus acutissima by using ChemJet tree injector. Three months after treatments, the treated saplings were cut and dipped into 1% fuchsin acid solution. There were significant differences in non-conductive area (%), discoloration area (%) and vertical discoloration length between the pathogen-injected and distilled water-injected control treatments. These results indicated that the pathogen is the causal agent for the dysfunction of water conductive tissue, which will finally result in wilt symptom. Re-isolation of the pathogen and PCR detection using specific primers for the pathogen also confirmed the presence of Rqm in the sapwood chips of the pathogen-injected saplings. These observations would be greatly applied to other related researches for evaluating the pathogenicity of tree wilt pathogens and biocontrol efficacy of the selected antagonistic microorganisms, in case that the wilt symptom is not easily shown by artificial inoculation of the causal agent.

• Food Science and Biotechnology
• /
• 제18권3호
• /
• pp.641-648
• /
• 2009

A one-step simultaneous immunchromatographic (OS-ICG) assay using colloidal gold-monoclonal antibody (gold-MAb) conjugates was developed for the rapid multianalysis of aflatoxin B1 (AFB1) and ochratoxin A (OTA) in feed samples. Visual detection limits for AFB1 and OTA were 0.5 and 2.5 ng/mL, respectively, and the results were obtained within 15 min. Matrix interference from the feed extracts was efficiently reduced by appropriate dilution with buffer. Cut-off values of the OS-ICG assay for the feed spiked with AFB1/OTA mixtures (5/5, 10/10, 25/25, 50/55, 100/100 ${\mu}g/kg$) were 10 and 50 ${\mu}g/kg$ for AFB1 and OTA. The comparative analyses of 65 feed samples by OS-ICG, enzyme-linked immunosorbent assay (ELISA), and high performance liquid chromatography (HPLC) showed good agreement. In this study, we confirmed that simultaneous analysis based on immunoassay is possible and it can be used as an on-site multianalysis of AFB1 and OTA in feed, food, and agricultural products.

• Journal of Communications and Networks
• /
• 제15권6호
• /
• pp.559-568
• /
• 2013

We report on the first error-free terahertz (THz) wireless communication at 0.310 THz for data rates up to 8.2 Gbps using a 18-GHz-bandwidth GaAs/AlGaAs field-effect transistor as a detector. This result demonstrates that low-cost commercially-available plasma-wave transistors whose cut-off frequency is far below THz frequencies can be employed in THz communication. Wireless communication over 50 cm is presented at 1.4 Gbps using a uni-travelling-carrier photodiode as a source. Transistor integration is detailed, as it is essential to avoid any deleterious signals that would prevent successful communication. We observed an improvement of the bit error rate with increasing input THz power, followed by a degradation at high input power. Such a degradation appears at lower powers if the photodiode bias is smaller. Higher-data-rate communication is demonstrated using a frequency-multiplied source thanks to higher output power. Bit-error-rate measurements at data rates up to 10 Gbps are performed for different input THz powers. As expected, bit error rates degrade as data rate increases. However, degraded communication is observed at some specific data rates. This effect is probably due to deleterious cavity effects and/or impedance mismatches. Using such a system, realtime uncompressed high-definition video signal is successfully and robustly transmitted.

• 한국통신학회논문지
• /
• 제29권11C호
• /
• pp.1518-1526
• /
• 2004

본 논문은 확장 QR-RLS 알고리즘을 이용한 시스토릭 어레이 구조를 갖는 적응 결정 궤환 등화기에 대해서 소개한다. 무선 이동 통신 시스템의 경우 빠른 시변환 채널로 인해 고속의 수렴 특성을 갖는 등화기가 필수적으로 요구된다. 최근에 이러한 성질을 만족하는 QR-RLS 알고리즘 기반의 등화기가 소개되었으며, RLS 알고리즘이 갖는 높은 수렴 속도와 시스토릭 어레이의 병렬 파이프라인 형태로 구현 가능함으로 인해 계산상의 높은 효율성을 가진다. 그러나 일반적인 QR-RLS 알고리즘은 별도의 등화기 가중치 추출과정을 필요로 하며, 이로 인해 적응 처리 과정을 완전한 파이프라인 형태로 수행하기는 어렵다. 본 논문에서는 확장 QR-RLS 알고리즘을 기반으로 제곱근 연산을 배제한 계산과정을 통해 채널 출력의 입력으로부터 가중치 갱신까지 완전환 파이프라인 방식으로 처리가 가능한 시스토릭 어레이 구조의 결정 궤환 등화기를 소개한다.

• 대한지역사회영양학회지
• /
• 제11권6호
• /
• pp.779-784
• /
• 2006

Several studies about hospital malnutrition have been reported that about more than 40% of hospitalized patients are having nutritional risk factors and hospital malnutrition presents a high prevalence. People in a more severe nutritional status ended up with a longer length of hospital stay and higher hospital cost. Nutrition screening tools identify individuals who are malnourished or at risk of becoming malnourished and who may benefit from nutritional support. For the early detection and treatment of malnourished hospital patients , few valid screening instruments fur Koreans exist. Therefore, the aim of this study was to develop a simple, reliable and valid malnutrition screening tool that could be used at hospital admission to identify adult patients at risk of malnutrition using medical electrical record data. Two hundred and one patients of the university affiliated medical center were assessed on nutritional status and classified as well nourished, moderately or severely malnourished by a Patient-Generated subjective global assessment (PG-SGA) being chosen as the 'gold standard' for defining malnutrition. The combination of nutrition screening questions with the highest sensitivity and specificity at prediction PG-SGA was termed the nutrition screening index (NSI). Odd ratio, and binary logistic regression were used to predict the best nutritional status predictors. Based on regression coefficient score, albumin less than 3.5 g/dl, body mass index (BMI) less than $18.5kg/m^2$, total lymphocyte count less than 900 and age over 65 were determined as the best set of NSI. By using best nutritional predictors receiver operating characteristic curve with the area under the curve, sensitivity and 1-specificity were analyzed to determine the best optimal cut-off point to decide normal or abnormal in nutritional status. Therefore simple and beneficial NSI was developed for identifying patients with severe malnutrition. Using NSI, nutritional information of the severe malnutrition patient should be shared with physicians and they should be cared for by clinical dietitians to improve their nutritional status.

• 한국멀티미디어학회논문지
• /
• 제3권2호
• /
• pp.121-132
• /
• 2000

본 대부분의 비디오 인덱싱 어플리케이션들은 빠르고 효과적인 저장, 브라우징, 검색 기법들을 요구한다. 현재까지 연구된 많은 기법들은 그 처리 영역이 화소 영역에 대해서만 다루어 왔다. 이런 접근은 멀티미디어 데이터가 일반적으로 압축된 형태로 저장되기 때문에 해독, 재압축에 따른 높은 오버헤드를 초래한다. 반면에 압축된 비디오 데이터가 주어질 때, 압축된 데이터를 직접 분석할 수 있다면 화소단위 처리에서 생기는 오버헤드를 피할 수 있다. 본 논문에서, 압축된 비디오 스트림 정보를 직접 분석하여 비디오 인덱싱에 유용한 특징들을 추출한다. 이러한 특징들을 이용하여 컷 검출을 위한 기법을 유도하여 스트림을 샷으로 분할한다. 또한 본 논문에서, 공간적 정보(DCT 계수)와 시간적 정보(움직임 벡터)를 이용하여 간단한 키 프레인 선택 기법과 효과적인 비디오 인덱싱 기법을 제안한다.

• 한국컴퓨터정보학회논문지
• /
• 제26권11호
• /
• pp.11-19
• /
• 2021

본 논문은 충전식 배터리의 단점을 보완하여 급속 충전과 방전이 가능하고 높은 전력 효율 및 반영구적인 충·방전 사이클 수명의 특성을 갖는 수퍼커패시터를 보조 전력 저장장치로 사용하여 전력 관리 시스템에 결합한 프로토타입 플랫폼을 제안한다. 본 논문의 플랫폼을 위해 물리적인 환경 변화에 따른 태양광 패널에서의 공급 전력 차단 혹은 재개 상태를 마이크로컨트롤러에 연결된 인터럽트를 통해 감지할 수 있는 기법을 개발하였다. 연속적인 전원 공급이 보장되지 않는 컴퓨팅 환경에서 데이터의 유실을 방지하기 위해 전원 공급이 차단되는 경우 휘발성 메모리에 있는 프로그램 문맥 및 데이터를 비휘발성 메모리로 이전하는 낮은 수준의 시스템 소프트웨어를 마이크로컨트롤러에 구현하였다. 실험을 통해 슈퍼커패시터가 보조 전력 저장장치로서 일시적 전원 공급에 효과적으로 하는지를 검증하였으며 다양한 벤치마크를 통해 전원 상태 감지 및 휘발성 메모리에서 비휘발성 메모리로의 프로그램 문맥 및 데이터의 이전 기법이 낮은 오버헤드를 갖음을 확인하였다.

• 고신대학교 의과대학 학술지
• /
• 제33권3호
• /
• pp.337-346
• /
• 2018

Objectives: Serum procalcitonin (PCT) is a specific biomarker that rises after bacterial infection, and levels of PCT are known to correlate with the severity and mortality of patients with pneumonia and sepsis. However, the usefulness of PCT levels in acute pyelonephritis is unknown. This study aimed to evaluate the effectiveness of using the PCT level as a predictive test for bacteremia in acute pyelonephritis. Methods: Between January 2012 and June 2013, 140 patients diagnosed with acute pyelonephritis were admitted to Haeundae Paik Hospital. Serum PCT, C-reactive protein (CRP), and white blood cell (WBC) levels at pre- and post- treatment were measured. Blood and urine cultures were obtained from all patients. The levels of PCT, CRP, and WBCs were each compared between the blood culture-positive and blood culture-negative groups to assess their effectiveness in predicting bacteremia. Results: Pre-treatment PCT level was 0.77 ng/mL (95% CI: 0.42-1.60 ng/mL) in the blood culture-negative group and 4.89 ng/mL (95% CI: 2.88-9.04 ng/mL) in the blood culture-positive group, and the increase between the two groups was statistically significant. The area under the receiver operating characteristic curve of PCT level for prediction of bacteremia was 0.728. A cut-off value of 1.23 ng/mL indicated a sensitivity of 79.0 % and specificity of 60.0 % for PCT level. Conclusions: Serum PCT level is a useful predictive test for bacteremia in acute pyelonephritis. Through the early detection of bacteremia, serum PCT level can help estimate the prognosis and predict complications such as sepsis.

• 한국정보통신학회논문지
• /
• 제24권6호
• /
• pp.759-767
• /
• 2020

본 논문에서는 인지 무선 통신을 위한 새로운 순환 신경망 기반 스펙트럼 센싱 기법을 제안한다. 제안하는 기법은 주사용자에 대한 정보가 전혀 없는 상황에서 에너지 검출을 통해 신호 존재 유무를 판단한다. 제안 기법은 센싱하고자 하는 전체 대역을 고려하여 수신신호를 고속으로 샘플링 후 이 신호의 FFT (fast Fourier transform)를 통해 주파수 스펙트럼으로 변환한다. 이 스펙트럼 신호는 채널 대역폭 단위로 자른 후 순환 신경망에 입력하여 해당 채널이 사용중인지 비어있는지 판정한다. 제안하는 기법의 성능은 컴퓨터 모의실험을 통해 확인하는데 그 결과에 따르면 기존 문턱값 기반 기법보다 2 [dB] 이상 우수하며 합성곱 신경망 기법과 유사한 성능을 보인다. 또한, 실제 실내환경에서 실험도 수행하는데 이 결과에 따르면 제안하는 기법이 기존 문턱값 기반 방식 및 합성곱 신경망 방식보다 4 [dB] 이상 우수한 성능을 보인다.