산소 부화가 초기 매연의 체류 시간에 따른 탄소화 과정에 미치는 영향

정용진(Yongjin Jung),오광철(Kwang Chul Oh),배충식(Choongsik Bae),신현동(Hyun Dong Shin) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.41

The carbonaceous process of incipient soot particles according to the residence time was investigated in a inverse diffusion flame with oxygen enrichment. Two-color-ratio pyrometry was used to measure the soot temperature. It revealed that the soot temperature corresponding to the maximum signal through 700 ㎚ band-pass filter remained between 2000 K and 2200 K below the flame height, which obtained from OH-Planar laser induced fluorescence. The C/H ratio, which is good quantitative indicator to judge the degree of carbonization, was strongly affected by the modified residence time. The modified residence time indicates conversion of the height from the beginning position of the yellow flame to the position corresponding to the temperature of 1600 K above the flame height.

Bluehole: Bluehole’s spectacular success in the video game industry

Yongjin Oh,이재원,Seungchul Lee Academy of Asian Business (AAB) 2018 Academy of Asian Business Review Vol.4 No.2

The purpose of this case study is to analyze the phenomenal global success of Bluehole, a game development company, which became the industry sensation through the release of ‘PlayerUnknown’s Battlegrounds (PUBG)’. This success story begins with an environmental analysis that explains the special opportunity the company found, how the global game industry has grown, the history of Bluehole and the company’s turning point. The success of PUBG is unique and trendy. Targeting the global video game market, a local Korean game development company went through an array of difficulties from the planning stage to the launch of the game and beyond. Bluehole decided to develop this game in a short period of time, and they tried a new marketing strategy that was, up to that time, far from a successful game formula. The company used influencers from Twitch as a marketing channel for the game, they released an early access version through Steam nine months before the full release, and sold the early-released version at the same price as the official launch version. One more point to highlight is that this game is a great example in which mods (a game format) became a fully-fledged, incredibly successful type of game. This research not only presents the success factors but also discusses the challenges confronting Bluehole, and makes suggestions to help Bluehole successfully and creatively maintain their business. This case study provides a profound analysis of the video game market and the opportunities that companies, especially start-ups, can take in this fast-changing field.

Effects of Aquatic Exercise on Upper Extremity Function and Postural Control During Reaching in Children With Cerebral Palsy

Jeon Yongjin,Jeon Hye-Seon,Yi Chung-hwi,Kwon Oh-yun,Cynn Heonseock,Oh Duckwon 한국전문물리치료학회 2023 한국전문물리치료학회지 Vol.30 No.2

Background: Despite the fact that aquatic exercise is one of the most popular alternative treatment methods for children with cerebral palsy (CP), there are few research regarding its effectiveness. Objects: The purpose of this study was to examine the effects of aquatic exercise on upper extremity function and postural control during reaching in children with CP. Methods: Ten participants (eight males and two females; 4–10 years; Gross Motor Function Classification System levels II–IV) with spastic diplegia were recruited to this study. The aquatic exercise program consisted of four modified movements that were selected from the Halliwick 10-point program to enhance upper extremity and trunk movements. The participants attended treatment two times a week for 6 weeks, averaging 35 minutes each session. The Box and Block Test (BBT), transferring pennies in the Bruininks-Oseretsky Test (BOT), and pediatric reaching test (PRT) scores were used as clinical measures. Three-dimensional motion analysis system was used to collect and analyze kinematic data. Differences in BBT and BOT values among pre-treatment, post-treatment, and retention (after 3 weeks) were analyzed using a Friedman test. In addition, the PRT scores and variables (movement time, hand velocity, straightness ratio, and number of movement units) from the three-dimensional motion analysis were tested using a Wilcoxon signed-rank test. The significance level was established at p < 0.05. When the results appeared to be statistically significant, a post-hoc test for multiple comparisons was performed with the Wilcoxon signed-rank test. Results: All clinical measures, which included BBT, transferring pennies of BOT, and PRT, were significantly increased between pre-intervention and post-intervention scores and between pre-intervention and retention scores after treatment (p = 0.001). Three-dimensional motion analysis mostly were significantly improved after treatment (p = 0.001). Conclusion: Aquatic exercise may help to improve body function, activity, and participation in children with varying types of physical disabilities.

Performance Test of Fully Automatic Potato Seeding Machine by In-situ Process of Cutting Seeds

( Yongjin Cho ),( Il Soo Choi ),( Jae Dong Kim ),( Jong-woo Oh ),( Dong-hoon Lee ) 한국농업기계학회 2017 바이오시스템공학 Vol.42 No.3

Purpose: To reduce the costs of potato seeds and labor of workers, a fully automatic in-situ seeding machine for cutting seed potatoes was developed. Methods: An experiment was conducted to evaluate the seeder performance of the prototype of potato planter by cutting seeds in farmlands from March to April 2017. The study tested the seeder performance at working speeds ranging from 0.28 to 0.45 m/s. The seeding rate and seeding distance were also investigated according to the planned distance between planted seeds from 20 to 30 cm, with 5 cm intervals. Results: Tests on the performance of the developed cutting blade on the automatic potato seeder show that whole potatoes should be used instead of half potatoes. The seeding rates were 88.8% and 82.5% for whole and half potatoes, respectively. When the tractor working speed was increased from 0.28 to 0.45 m/s, the successful seeding rate decreased from 98.8% to 96.3%, respectively. However, with planted seed d istances of 20, 25, and 30 cm, the successful s eeding r ates were near 98%. Conclusions: The developed automatic potato seeder can to improve the labor productivity and cultivation environment of potato farms by the mechanization of the seeding process, which is currently associated with high-labor, -costs, and -hours. Therefore, based on this study, the developed automatic potato seeder provides the mechanization necessary for improved potato cultivation conditions in farmlands.

Research for Monitoring the Behavior of the Sows using Ultrasonic Sensor

( Yongjin Cho ),( Jong-woo Oh ),( Dong-hoon Lee ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Data collected in-situ from agriculture sensors has potential to improve the efficiency and accuracy of estimates on agricultural information. To estimate the abnormal condition of sow were almost performed by empirical methods such as observation directly by experts. However, the empirical method is inefficient way due to huge labor- and time-consuming. The experiments were performed in normal condition and abnormal condition of sow. The data obtained from the ultrasonic sensor is stored in usb flash driver attached to a microcontroller. The data acquired by the ultrasonic sensor was re-organized using visual C+, and spatial statistical interpolation were analyzed using the MATLAB. The Real time positioning system (RTLS) technology using streaming video and data of ultrasonic-based collaborative techniques is used to assess the health status of animals and to find the total distance the animals to statistically investigate the relationship between health condition and ultrasonic data. In the case of the normal condition, all sensor data was steadily measured in the upper, middle, and lower positions. However, the abnormal condition was showed that sensor data was concentrated at the lower position. In this way, the difference between the normal and abnormal condition is clearly shown, so that the manager can analyze the state of the sow.

Estimation of Crop Destruction from Ingestion by Animals in Grazing Field using Phase Correlation Analysis of Distorted Remote Image

( Yongjin Cho ),( Jong-woo Oh ),( Dong-hoon Lee ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

This study was accomplished to estimate how fast animals destroyed grazing field as ingestion of crop using frequency domain analysis on drone image. The image were collected at the North Carolina A&T State University farm located in Greensboro, North Carolina every day, unless it rained or was too windy. Some limitations to take into account was that the drone did not collect images in the same aligned position every time. Further, the images produced from the drone were distorted by a fisheye effect. The experiment observed for two weeks based on how the animals destroyed the field from September 2016. Combining with the distinctive position of every picture taken, the images became ineffective pieces of information and evidence. MATLAB was utilized in efforts to adjust the picture for effective and accurate analysis to compare the fields after each day the animals were introduced to the grazing field. In step 1, image translation was identified between two timely adjacent images of rotation and distortion by next try. After cropping images from the center of each original image, the image translation was estimated by using imregcorr function, and the size of the cropped image was gradually enlarged. In step 2, similarities between two crop images calibrated by identified translation was analyzed as follows; a) Crop first image from center of first image, b) Crop second image from translated location in second image, c) Identify similarities between two cropped images using phase-correlation, d) Gradually enlarge the size of cropped image. After repeating steps 1 and 2 with the next adjacent pairs of images, adjacent images could be scaled to dry matter consumption ratio (assuming that the first image is 100% of forages, and the last image is 0% of forages). In conclusion, the most field was destroyed by animals between the 10th and 11th day after the animals were introduced into the grazing field. Air-bone image was collected by drone including systematic distortion error can be calibrated by consideration about frequency domain analysis such as phase correlation.

Research of Non-integeral Spatial Interpolation for Precise Identifying Soybean Location under Plastic Mulching

( Yongjin Cho ),( Yeji Yun ),( Kyou-seung Lee ),( Jong-woo Oh ),( Donghoon Lee ) 한국농업기계학회 2017 한국농업기계학회 학술발표논문집 Vol.22 No.1

Most crop damages have been occurred by vermin(e.g., wild birds and herbivores) during the period between seeding and the cotyledon level. In this study, to minimize the damage by vermin and acquire the benefits such as protection against weeds and maintenance of water content in soil, immediately vinyl mulching after seeding was devised. Vinyl mulching has been generally covered with black color vinyl, that crop seeding locations cannot be detected by visible light range. Before punching vinyl, non-contact and non-destructive methods that can continuously determine the locations are necessary. In this study, a crop position detection method was studied that uses infrared thermal image sensor to determine the cotyledon position under vinyl mulch. The moving system for acquiring image arrays has been developed for continuously detecting crop locations under plastic mulching on the field. A sliding mechanical device was developed to move the sensor, which were arranged in the form of a linear array, perpendicular to the array using a micro-controller integrated with a stepping motor. The experiments were conducted while moving 4.00 cm/s speed of the IR sensor by the rotational speed of the stepping motor based on a digital pulse width modulation signal from the micro-controller. The acquired images were calibrated with the spatial image correlation. The collected data were processed using moving averaging on interpolation to determine the frame where the variance was the smallest in resolution units of 1.02 cm. For this study, the spline method was relatively faster than the other polynomial interpolation methods, because it has a lower maximum order of formulation when using a system such as the tridiagonal linear equation system which provided the capability of real-time processing. The temperature distribution corresponding to the distance between the crops was 10 cm, and the more clearly the leaf pattern of the crop was visually confirmed. The frequency difference was decreased, as the number of overlapped pixels was increased. Also the wave pattern of points where the crops were recognized were reduced.

Research of Phase Correlation Method for Identifying Quantitative Similarity in Adjacent Real-time Streaming Frame

( Yongjin Cho ),( Yeji Yun ),( Kyou-seung Lee ),( Jong-woo Oh ),( Donghoon Lee ) 한국농업기계학회 2017 한국농업기계학회 학술발표논문집 Vol.22 No.1

To minimize the damage by wild birds and acquire the benefits such as protection against weeds and maintenance of water content in soil, the mulching black color vinyl after seeding should be carried out. Non-contact and non-destructive methods that can continuously determine the locations are necessary. In this study, a crop position detection method was studied that uses infrared thermal image sensor to determine the cotyledon position under vinyl mulch. The moving system for acquiring image arrays has been developed for continuously detecting crop locations under plastic mulching on the field. A sliding mechanical device was developed to move the sensor, which were arranged in the form of a linear array, perpendicular to the array using a micro-controller integrated with a stepping motor. The experiments were conducted while moving 4.00 cm/s speed of the IR sensor by the rotational speed of the stepping motor based on a digital pulse width modulation signal from the micro-controller. The acquired images were calibrated with the spatial image correlation. The collected data were processed using moving averaging on interpolation to determine the frame where the variance was the smallest in resolution units of 1.02 cm. Non-linear integral interpolation was one of method for analyzing the frequency using the normalization image and then arbitrarily increasing the limited data value of 16 × 4 pixels in one frame. It was a method to relatively reduce the size of overlapping pixels by arbitrarily increasing the limited data value. The splitted frames into 0.1 units instead of 1 pixel can propose more than 10 times more accurate and original method than the existing correction method. The non-integral calibration method was conducted by applying the subdivision method to the pixels to find the optimal correction resolution based on the first reversed frequency. In order to find a correct resolution, the expected location of the first crop was indicated on near pixel 4 in the inversion frequency. For the most optimized resolution, the pixel was divided by 0.4 pixel instead of one pixel to find out where the lowest frequency exists.

Cholera Toxin Production during Anaerobic Trimethylamine <i>N</i>-Oxide Respiration Is Mediated by Stringent Response in <i>Vibrio cholerae</i>

Oh, Young Taek,Park, Yongjin,Yoon, Mi Young,Bari, Wasimul,Go, Junhyeok,Min, Kyung Bae,Raskin, David M.,Lee, Kang-Mu,Yoon, Sang Sun American Society for Biochemistry and Molecular Bi 2014 The Journal of biological chemistry Vol.289 No.19

<P>As a facultative anaerobe, <I>Vibrio cholerae</I> can grow by anaerobic respiration. Production of cholera toxin (CT), a major virulence factor of <I>V. cholerae</I>, is highly promoted during anaerobic growth using trimethylamine <I>N</I>-oxide (TMAO) as an alternative electron acceptor. Here, we investigated the molecular mechanisms of TMAO-stimulated CT production and uncovered the crucial involvement of stringent response in this process. <I>V. cholerae</I> 7th pandemic strain N16961 produced a significantly elevated level of ppGpp, the bacterial stringent response alarmone, during anaerobic TMAO respiration. Bacterial viability was impaired, and DNA replication was also affected under the same growth condition, further suggesting that stringent response is induced. A Δ<I>relA</I> Δ<I>spoT</I> ppGpp overproducer strain produced an enhanced level of CT, whereas anaerobic growth via TMAO respiration was severely inhibited. In contrast, a ppGpp-null strain (Δ<I>relA</I> Δ<I>spoT</I> Δ<I>relV</I>) grew substantially better, but produced no CT, suggesting that CT production and bacterial growth are inversely regulated in response to ppGpp accumulation. Bacterial capability to produce CT was completely lost when the <I>dksA</I> gene, which encodes a protein that works cooperatively with ppGpp, was deleted. In the Δ<I>dksA</I> mutant, stringent response growth inhibition was alleviated, further supporting the inverse regulation of CT production and anaerobic growth. <I>In vivo</I> virulence of Δ<I>relA</I> Δ<I>spoT</I> Δ<I>relV</I> or Δ<I>dksA</I> mutants was significantly attenuated. The Δ<I>relA</I> Δ<I>spoT</I> mutant maintained virulence when infected with exogenous TMAO despite its defective growth. Together, our results reveal that stringent response is activated under TMAO-stimulated anaerobic growth, and it regulates CT production in a growth-dependent manner in <I>V. cholerae</I>.</P>

실시간 LWIR 밴드 영상 처리를 위한 병렬 클러스터링 기술

조용진 ( Yongjin Cho ),이규승 ( Kyou-seung Lee ),홍성하 ( Seongha Hong ),오종우 ( Jong-woo Oh ),이동훈 ( Donghoon Lee ) 한국농업기계학회 2017 한국농업기계학회 학술발표논문집 Vol.22 No.1

비닐포장 하부에 위치한 콩의 생장 초기에 발생한 초엽을 인식하기 위한 연구를 수행중이다. 선행 연구에서 비닐포장에 접촉한 콩 초엽으로 인해 비닐포장 상부 표면의 열 반응 분포에 변화가 있음을 발견하였다. 현장에서 주행 중에 콩 초엽의 위치를 실시간으로 인식하고 연동된 선형 또는 회전형 엑츄에이터를 제어하여 정확한 위치에 천공을 수행하기 위해서는 계측 시스템과 제어 시스템간의 시간적 차이를 최소할 수 있는 실시간 신호 처리 기술이 필수적이다. 선행 연구에서 사용한 다중 IR 센서의 분해능은 16×4 pixel이며 주파수는 3 Hz로, 폭이 30cm 내외인 비닐포장 상부의 정밀 분석에 한계가 있음을 발견하였다. 이를 해결하기 위하여 분해능과 계측 주기를 개선할 수 있는 초소형 (1 cm × 1 cm × 1 cm) 열화상 센서를 이용하였다. LWIR(Longwave infrared)영역에 해당하는 8μm~14μm의 영역에서 0.05℃의 분해능을 보이는 Lepton^TM (500-0690-00, FLIR, Goleta, CA)모델을 사용하였다. 프레임당 80×60 픽셀의 정보가 2Byte의 단위로 계측이 되며 9 Hz의 주파수로 대상면의 열 분포를 측정할 수 있다. 이론적으로 초당 정보전송량은 86,400 Byte (80×60×2×9)이며, 1 m를 진행하는 주행형 천공기에 적용할 경우 1 프레임당 10cm정도의 면적을 측정하므로, 최대 위치 판정 분해능은 약 10 cm / 60 pixel = 0.17 cm/pixel로 상대적으로 정밀한 위치 판별이 가능하다. 80×60×2 Byte의 정보를 0.1초 이내에 분석해야 하는 기술적 과제를 해결하기 위하여 천공 작업기에 적합한 상용 SBC(Single board computer)의 클럭 속도(1 Ghz)로 처리 가능한 공간분포 분석 알고리즘을 개발하였다. 전체 이미지 도메인을 한 번에 분석하는데 소요되는 시간을 최소화하기 위하여 공간정보 행렬을 균등히 배분하고 별도의 프로세서에서 Feature를 분석한 후 개별 프로세서의 결과를 경합식으로 판정하는 기술을 연구하였다. 오픈 소스인 MPICH(www.mpich.org) 라이브러리를 이용하여 개발한 신호 분석 프로그램을 클러스터링으로 연동된 개별 코어에 설치/수행 하였다. 2D 행렬인열분포 정보를 공간적으로 균등 분배하여 개별 코어에서 행렬의 Spatial domain analysis를 수행하였다. 20×20의 클러스터링 단위를 이용할 경우 총 12개의 코어가 필요하였으며, 초당 10회의 연산이 가능함을 확인하였다. 병렬 클러스터링 기술을 이용하여 1m/s 내외의 주행 속도에 대응이 가능한 비닐포장 상부열 분포 분석 시스템을 구현하였다.