Earticle

Precise step detection is an essential task for pedestrian dead reckoning based navigation. This study presents a novel step detection method using a Dynamic Weight Integrated Fuzzy C-Means (DWIFCM) algorithm. It utilizes the statistical criteria extracted from the readings of accelerometer sensors and improves the accuracy of step detection. The performance of the proposed step detection technique is evaluated by considering the variations in walking patterns of the pedestrian in different landscapes of the path. The experimental results yield that the proposed method outperforms among the existing benchmark techniques.

MEMs IMU(Inertial Measurement Unit)를 이용한 보행자추측항법 (pedestrian dead-reckoning, PDR) 시스템은 실내 환경에서 보행자의 위치를 추정하는 기술로, 외부 인프라를 요구하지 않고 저비용으로 위치 추정이 가능한 장점으로 인해 이를 활용한 연구가 활발히 이루어지고 있다. 하지만 PDR 시스템은 센서의 낮은 정밀도 및 시간과 거리에 비례하여 누적되는 오차로 인해 신뢰도가 저하되는 문제가 있어 정확도 향상을 위한 알고리즘과 필터 설계가 중요하다. PDR 시스템은 보행자의 걸음을 판단하는 걸음 검출과정과 이동거리를 추정하는 보폭추정 그리고 보행방향을 결정하는 방향추정 과정을 거치게 되며, 걸음과 보폭은 위치 추정 단계에서 이동 거리 오차에 영향을 준 다. 걸음 검출 및 보폭 추정은 일반적으로 가속도 센서의 측정 데이터를 기반으로 이루어지는데, 중력가속도 기반의 걸음 검출은 비교적 정확하게 측정 가능한 반면 사람의 걸음마다 달라지는 보폭을 반영하지 못하는 문제점이 있다. 본 논문에서는 각속도 센서의 측정 데이터를 이용한 걸음 검출 및 보폭 추정 방법을 제안하였고, 제안하는 방법을 발 부착형 PDR 시스템에 적용하여 실험을 통해 걸음 검출 및 보폭 추정의 정확도를 평가하였다.

PDR system using IMU is proposed as a method for estimating the position in an indoor environment. The PDR system has the advantage of estimating the position without any additional external devices, however, it requires an algorithm and filter design to improve accuracy owing to precision and noise problems. The PDR system estimates the position through step detection, step length estimation, and heading estimation. In the position estimation procedure, the detected step and estimated step length affect the movement distance error. Step detection and step length estimation are generally based on measurement data from an accelerometer. While step detection using gravity acceleration is relatively accurate, it can not reflect the step length that varies with each step of the person. In this paper, a step detection and step length estimation method using gyroscope data is proposed. The proposed method was applied to the foot-mounted PDR system and the accuracy of the step detection and step length estimation was evaluated through experiments.

Matrix metalloproteinases (MMPs) have been shown to be abundant in pathological situations such as tumor tissue, osteoarthritis (OA) and rheumatoid arthritis (RA). The extent of MMPs detected in biological samples provides important information for diagnosis, prognosis, and therapy monitoring of diseases relating with MMP. A number of attempts have been made to detect activities of MMPs in biological samples and to evaluate the effects of MMP inhibitors. Previously, we have demonstrated that a highly efficient MMP fluorogenic probe, which is a pair consisting of a fluorophore (Cy5.5) and a quencher (BHQ-3), can detect MMP-13 in OA-induced rat model with a low background and significant signal recovery, enabling a highly sensitive visual detection in vitro and in vivo. In this study, we developed a new high-throughput MMP detection kit based on a 96-well microplate by immobilizing a rationale designed chitosan-conjugated fluorogenic probe and investigated whether this new MMP detection kit can monitor MMP activity. Glycol chitosan (GC), natural polymer, was used as a linker to immobilize and amplify MMP fluorogenic probe on a 96-well microplate for a highly sensitive detection. When MMP enzymes were simply added and incubated in a 96-well microplate immobilized with GCconjugated MMP probe, the fluorescence of each well was recovered and the fluorescence intensity showed distinct difference within minutes through Kodak Image Station. Furthermore, recovery of fluorescent signals in the MMP detection kit was proportional to concentrations of immobilized GCconjugated MMP probe and, importantly, treated concentrations of pure MMP enzymes. The detection kit is most specific for MMPs, compared with other enzymes including caspase-3 and 20s proteasome. Additionally, the detection kit was used to detect MMP activity in biological samples such as synovial fluids from OA patients and showed the fluorescence intensity to correlate with the stage of OA development. The detection kit may be applicable in detecting MMP activity in other various biological samples and evaluate the effects of MMP inhibitors in a rapid and easy fashion.

Rapid diagnosis of bacterial infections has been considered as important criteria for a patient management and an appropriate therapy of bacteria-induced disease in the early phase. Among several techniques, CE-SSCP combined with 16S rRNA gene-specific PCR takes a huge attention due to its benefits such as high sensitivity, resolution and reproducibility. However, as in any other PCR-based technology, multiplex detection and quantification is a major hurdle for this method because of primer dimer formation and non-specific amplification by multiple sets of primers. In this study, we developed a novel technique for multiplex detection and quantification of pathogens by CE-SSCP coupled with multiplex asymmetric PCR using common primers via template-tagging. For linearly amplifying the reversed transcripts of 16S rRNAs from nine septicemia-inducing pathogens, the reverse transcripts were tagged with the common sequence and subsequently amplified by asymmetric PCR using the common primers. After the amplification, the amplicons were separated and quantified by CE-SSCP. The results illustrated the potentials of this method in the diagnosis of the infectious disease.

Conventional point-of-care (POC) devices need to be more convenient because blood sampling and sample analysis are implemented in separate devices. Therefore, we have developed a one-step microfluidic POC device which can carry out blood sampling and sample analysis simultaneously on a device. The one-step microfluidic device has three components, a microneedle (an inner diameter: 80 μm) and a micropump for blood sampling and a microchannel for immuoassay. The micropump is a cylinder (dimameter: 9 mm, height: 15 mm) on a flexible thin film (1 mm tick) made of elastic polymer polydimethylsiloxane. The microchannel is fabricated with UV-curable polymer, Norland Optical Adhesive (NOA63), by contact printing method. Then, the surface of the channel was coated with PDMS nanolayer and modified to be hydrophilic by treating oxygen plasma. Finally, the microneedle and the micropump were assembled by bonding after oxygen plasma treatment and the microneedle was bonded to the side of the micropump. We observed the one-step microfluidic device could pump 300 ㎕ distilled water and blood mimicking solution as well. Then, the pumped sample solution was spontaneously flowed into the hydrophilic microchannel sequentially. Therefore, the one step microfluidic device can be used as a POC device for quick and convenient diagnosis on site.

In this paper, we proposed a new fast detection method of copy-move forgery image using two step search algorithm in the spatial domain. We proposed a new two step search algorithm for copy-moved forgery image detection. The performance of the proposed method is experimented on several forged images. Our two step search algorithm reduced 96.82% computational complexity more than conventional algorithms for copy-move forgery image detection. The block distortion measure (BDM) of the two step search algorithm is sufficient by 2 pixels checking points instead of 64 pixels checking points for exhaustive search in the not copy-moved forgery image regions. Most blocks of the images constitute not copy-moved forgery images. Therefore, we can reduce computational complexity more than conventional methods. We didn’t use any exhaustive search method and frequency domain (ex. DCT, Wavelet Transform) to reduce computational complexity in this paper.

스마트폰을 이용한 실내에서의 위치 기술이 다양하게 연구되고 있다. 그 중 스마트폰에 내장된 가속도 센서와 자이로 센서를 이용한 위치 추적 기술은 WiFi fingerprint 기술 등과 함께 연동되어 많이 사용되고 있다. 센서를 이용한 위치 추적 기술은 오래 전부터 사용되어 왔으나, 스마트폰의 경우 센서의 성능이 좋지 않고 사용자가 스마트폰을 일정한 자세로 들고 이동하는 등 사용 환경이 특이하다. 따라서 스마트폰 환경에서 위치 추적의 정확도를 높이기 위해서는 고유의 환경에서 적절 한 알고리즘을 연구 개발해야 한다. 본 논문에서는 사용자의 이동 걸음 수 검출 알고리즘인 주파수 분석 방식, 최대 최소 가속도의 합 방식 및 적응형 임계값 방식에 대한 다양한 실험 환경에서의 성능을 분석하고, 가장 정확한 방식을 선정한다.

Various techniques for indoor positioning using a smart phone have been studied. Among them, the positioning technology using the acceleration sensor and the gyro sensor built in the smartphone is widely used in conjunction with the WiFi fingerprint technology. The location tracking technology using sensors has been used for a long time, but the performance environment of the smartphone is poor and the user is moving with the smartphone in a certain posture. Therefore, in order to improve the accuracy of location tracking in a smartphone environment, it is necessary to study and develop appropriate algorithms in a mobile environment. In this paper, we analyze the performances of frequency analysis method, maximum sum of minimum acceleration method and adaptive threshold method, which are the user's moving step count detection algorithms, and determine the most accurate method.

Gait analysis through wearable sensors is becoming a key research topic in mobile. In gait analysis, step detection is one of the most important processes that will lay down the foundation for future implementation. In this paper, we will propose a simpler algorithm to determine and analyze the steps using accelerometer sensor built-in mobile phone that physically placed into the trouser pocket. This is the location where most of mobile devices are. With 5 volunteers walking in 160 seconds, the accuracy of this method is approximately 98.5%.

We developed a multiplex PCR (mPCR) assay to simultaneously detect Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Ureaplasma urealyticum, Corynebacterium spp. and seudomona aeruginosa. This method employs a single tube and multiple specific primers which yield 200, 281, 346, 423, 542, and 1,427 bp PCR products, respectively. All the PCR products were easily detected by agarose gel electrophoresis and were sequenced to confirm the specificity of the reactions. To test this method, DNA extracted from urine samples was collected from 96 sexually transmitted disease or prostatitis patients at a local hospital clinical center, and were subjected to the mPCR assay. The resulting amplicons were cloned and sequenced to exactly match the sequences of known pathogenic isolates. N. gonorrhoeae and Corynebacterium spp. were the most frequently observed pathogens found in the STDs and prostatitis patients, respectively. Unexpectedly, P. aeruginosa was also detected in some of the STD and prostatitis samples. More than one pathogen species was found in 10% and 80.7% of STD and prostatitis samples, respectively, indicating that STD and prostatitis patients may have other undiagnosed and associates. The sensitivity of the assay was determined by sing purified DNA from six pathogenic laboratory strains and revealed that this technique could detect pathogenic DNA at concentrations ranging from 0.018 to $1.899\;pg/{\mu}l$. Moreover, the specificities of this assay were found to be highly efficient. Thus, this mPCR assay may be useful for the rapid diagnosis of causative infectious STDs and prostatitis. useful for the infectious STDs and prostatitis.

We propose a new approach called as a peak time approach for faster detection of step initiation for the lower limb exoskeleton. As faster detection of step initiation is an important criterion in evaluating the lower limb exoskeleton, many studies have investigated approaches to detect step initiation faster, including using electromyography, the center of pressure, the heel-off time and the toe-off time. In this study, we will utilize vertical ground reaction force events to detect step initiation, and compare our approach with prior approaches. Additionally, we will predict the first step's heel strike time with vertical ground reaction force events from multiple regression equations to support our approach. The lower limb exoskeleton should assist the operator's movement much faster and more reliably with our approach.

Background: The object of this study was to examine whether a new protocol including step-sectioning and immunohistochemistry (IHC) staining of axillary sentinel nodes (SN) would lead to detection of more metastases in patients with breast cancer. Materials and Methods: Sixty-nine tumor free sentinel lymph nodes were examined. Step frozen sectioning was performed on formalin fixed SN and stained both by hematoxylin and eosin (H and E) and cytokeratin markers using IHC. Any tumoral cell in IHC stained slides were considered as a positive result. Metastases up to 0.2 mm were considered as isolated tumor cells and 0.2 up to 2 mm as micrometastasis. Results: Mean age of the patients was $48.7{\pm}12.2$ years. Step sectioning of the SN revealed 11 involved by metastasis which was statistically significant (p<0.001). Furthermore, 15 (21.7%) of the patients revealed positive results in IHC staining for pan-CK marker and this was also statistically significant (p=0.001). Ten patients had tumoral involvement in lymph nodes harvested from axillary dissection and 4 out of 15 lymph nodes with positive result for CK marker were isolated tumor cells. However, 4 of 10 patients with tumor positive lymph nodes in axillary dissection were negative for CK marker and in contrast 6 of the pan-CK positive SN were in patients with tumor-free axillary lymph nodes. Conclusions: Both IHC and step sectioning improve the detection rate of metastases. Considering the similar power of these two methods, we recommend using either IHC staining or step sectioning for better evaluation of harvested SNs.

A method is proposed to achieve improved number plate detection for mobile devices by applying a two-step convolutional neural network (CNN) approach. Supervised CNN-verified car detection is processed first. In the second step, we apply the detected car regions to the second CNN-verifier for number plate detection. Since mobile devices are limited in computing power, we propose a fast method to detect number plates. We expect to use in the field of intelligent transportation systems (ITS).

이 논문에서는 클러터 환경에서 최적의 거리와 거리방향 속도 추적을 위한 검출문턱값과 파형 파라미터의 one-step-ahead 제어를 제시하였다. 파형 파라미터의 최적 제어는 파형 파라미터에 대한 제약 조건이 있는 상황에서 추적 성능지수를 최소화하는 것이다. 성능지수는 항적분실확률과 추정오차 공분산행렬의 함수로 표현하였다. 항적분실확률과 오차 공분산행렬은 하이브리드 알고리듬을 이용하여 얻었다. 거짓 검출과 클러터 간섭의 영향은 이 성능 예측 알고리듬에서 함께 고려되었다. 여기서 제안한 one-step-ahead 제어의 추적 성능을 여러 가지 수치실험을 통해 확인하였고, 이 제어 방법은 유한 구간의 최적화 결과로부터 얻어진 경험적인 방법이다.

In this paper, we consider one-step-ahead control of waveform parameters (pulse amplitudes and lengths, and FM sweep rate) as well as detection thresholds for optimal range and range-rate tracking in clutter. The optimal control of the combined parameter set minimizes a tracking performance index under a set of parameter constraints. The performance index includes the probability of track loss and a function of estimation error covariances. The track loss probability and the error covariance are predicted using a hybrid conditional average algorithm The effect of the false alarms and clutter interference is taken into account in the prediction. Tracking performance of the one-step-ahead control is presented for several examples and compared with a control strategy heuristically derived from a finite horizon optimization.

Background: Fast identification of Candida glabrata is important, because empirical antifungal therapy for fungemia with C. glabrata and non-C. glabrata varies. We proposed an algorithm for rapid presumptive diagnosis to identify fungemia with C. glabrata using earlier or only growth from anaerobic bottles and longer time to positivity (TTP) in blood cultures. Methods: Positivity and TTP using the BacT/Alert 3D system (bioMerieux Inc, USA) with resin bottles (FA Plus and FN Plus) were analyzed in 215 candidemia patients from June 2014 to June 2016 in a university-affiliated hospital in Korea. Results: A higher proportion of earlier or only growth from anaerobic bottles was observed in C. glabrata (38.8%, 7/18) than in C. albicans (7.6%, 8/105), C. parapsilosis (10.5%, 4/138), and C. tropicalis (9.2%, 5/54) (P=0.006). The mean (±standard deviation) TTP for C. glabrata was 41.7 h (±16.3 h) compared with 26.7 h (±15.9 h) for C. albicans, 33.4 h (±8.4 h) for C. parapsilosis, and 23.1 h (±17.3 h) for C. tropicalis (P＜0.0001). We could predict fungemia with C. glabrata with a sensitivity of 94.4%, specificity of 63.9%, positive predictive value of 19.3%, and negative predictive value of 99.2% using a two-step algorithm: earlier or only growth from anaerobic bottles and TTP ＞31.4 h. Conclusion: This two-step algorithm in the BacT/Alert 3D system could be the basis for an initial empirical antifungal therapy for fungemia with C. glabrata prior to final identification. (Ann Clin Microbiol 2018;21:-27)

Nickel ferrite (NiFe2O4) ceramics were prepared by combustion in air and sintered using different two-step sintering processes,classified as condition I and condition II. Both conditions employed a first-step temperature (T1) of 1200 °C for 1 minute. Inthe second step, the temperature (T2) was reduced to 1150 °C, with no holding time for condition I and a 240-minute hold forcondition II. XRD analysis confirmed the formation of a single-phase NiFe2O4 with no phase transformations during sintering. NiFe2O4 ceramic from condition II exhibited higher density (3.71 ± 0.04 g/cm3) and flexural strength (17.32 ± 0.52 MPa) thanthose from condition I (3.43 ± 0.06 g/cm3 and 10.19 ± 0.83 MPa). Despite an 8% increase in density and an 11.68% reductionin porosity, the strength improved by ~52%, highlighting the role of extended holding time. However, the higher porosityand specific surface area (0.76 m²/g) of NiFe2O4 ceramic from condition I enhanced gas-sensing properties. The NiFe2O4ceramics responded consistently to variations in LPG flow rate, indicating p-type semiconductor behavior. Ceramic fromcondition I showed stronger and faster responses to LPG at room temperature (S = 0.76, t90 = 20.47 s, trec = 1.29 min) thanceramic sintered from condition II (S = 0.46). The sensitivity of the ceramic from condition I at various LPG concentrationswas 7.31 × 10-6 ppm-1.

In this paper, a motion detection algorithm which works well in low illumination environment is proposed. By using the level set based bimodal motion segmentation, the algorithm obtains an automatic segmentation of the motion region and the spurious regions due to the large CCD noise in low illumination environment are removed effectively.

We proposed a fast detection of copy-move image forgery using four step search algorithm in the spatial domain. In the four-step search algorithm, the search area is 21 (-10 ~ +10), and the number of pixels to be scanned is 33. Our algorithm reduced computational complexity more than conventional copy move image forgery methods. The proposed method reduced 92.34 % of computational complexity compare to exhaustive search algorithm.

A two-step triplex PCR assay targeting the mecA, femA, and nuc genes was developed for the detection of methicillin resistance genes harbored by some Staphylococcus aureus isolates and for the simultaneous identification of such isolates at the species level. The triplex PCR revealed the presence of the femA and nuc genes in all the S. aureus isolates examined (n=105). Forty-four clinical isolates were mecA positive and no foodborne isolates were mecA positive. The PCR results had a 98 or 99% correlation with the results of PBP2a latex agglutination tests or oxacillin susceptibility tests, respectively.