• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.1
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• pp.77-88
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• 2022

With the development and popularization of drone manufacturing technology, the drone market, which was mainly focused on industry, agriculture, and military, is also showing great growth in individual and commercial markets. Among them, DJI has a high share in the personal and commercial drone market, and accordingly, forensic analysis of DJI drones is drawing attention. In particular, when stealing and analyzing drones used in criminal acts, a technology to interpret flight logs recording drone flight paths and hardware information is needed, which inevitably applies drone models due to differences in decryption methods. Therefore, when an unidentified drone is acquired from the perspective of a digital forensic investigator, a clear classification of a drone model to which analysis can be applied is required. This paper proposes a method of extracting and analyzing artifacts of DJI drones through forensics, and analyzes media data analysis and flight log analysis results and decryption methods for three drone models with different release years of DJI. Finally, drones in the DJI product line are classified according to whether the commercialized DJI drone flight log is decrypted.

• Digital Contents
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• no.2 s.81
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• pp.61-63
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• 2000

다우존스 인터랙티브사가 정보 전문가들에게 독점 DJI 소프트웨어 사용을 중지하고 djinteractive.com의 DJI-Web 인터페이스를 사용하도록 권했을때, 정보 전문가들은 이렇게 대답했다. "하지만 우리는 응답시간이 빠른 소프트웨어가 좋습니다!" 논의 끝에 DJI사는 생각을 바꾸어 올해 초에 DJI-윈도우 소프트웨어 지원만을 계속할 것이 아니라 업그레이드하겠다고 발표했다. 몇 달 지연되기는 했지만 마침내 새로운 DJI-윈도우 소프트웨어가 지난 여름에 출시되었다.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.325-333
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• 2007

One bacterium with high proteinase production and spore-forming ability was isolated from korean traditional soybean paste(doenjang). The isolated strain was identified as Bacillus subtilis, based on gram-staining, biochemical properties and l6S rRNA gene sequencing, and designated as B. subtilis DJI. Its growth rate was very fast, and it reached its stationary phase within 9 h, and then started to form spores. Bacterial-koji and doenjang were prepared using B. subtilis DJI. Chemical components of the doenjang were determined after 2 months of aging period: amino nitrogen 507 mg%, crude protein 14.3%, crude fat 4.8% and water 54.9%. The composition of total and free amino acids and their ratios of doenjang were changed during the aging period. Among total amino acids in DJI doenjang, glutamic acid, aspartic acid, leucine and arginine were the major amino acids. The fibrinolytic activities of DJI doenjang and traditional doenjangs were 909.7 units/ml and $363.3{\sim}618.6\;units/ml$, respectively. Flavor compounds of DJI doenjang and traditional doenjang were extracted by SDE(simultaneous steam distillation and extraction), and analyzed by GC/MS; DJI doenjang possessed the typically favorable flavor compounds in traditional korean doenjang, with reduced off-flavor compounds.

• Food Science and Preservation
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• v.16 no.4
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• pp.554-561
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• 2009

We investigated the antioxidative effects of solvent extracts of doenjang fermented using Bacillus subtilis DJI (DJI doenjang) in vitro. The solvents used for extraction were ethanol, n-hexane, and water. The antioxidative activities of DJI doenjang solvent extracts were measured by estimation of peroxide value, the presence of linoleic acid level, and nitrite scavenging activity, the Rancimat test, and 1,1-diphenyl-2-picryl hydrazyl (DPPH) free-radical generation, in comparison with the commercial antioxidant butylated hydroxytoluene (BHT). The peroxide value of an ethanol extract was lower than those obtained using n-hexane and water extracts. Furthermore, the peroxide value of the ethanol extract was similar to that obtained after BHT treatment. The nitrite scavenging activity was 23.36% after addition of 600 ppm DJI doenjang ethanol extract, and the DPPH free-radical scavenging activity was 19.06% under same condition, which shows that DJI doenjang ethanol extract exhibited lower antioxidative capacities than did BHT. In the Rancimat test, the ethanol extract (11.20 min induction time), n-hexane extract (7.58 min induction time), and water extract (8.26 min induction time) after treatment with 600 ppm DJI doenjang extracts demonstrated longer induction periods than did BHT (6.94 min). These results indicate that DJI doenjang has potential anti-oxidative activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1699-1706
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• 2009

This study was conducted to investigate the antioxidative effects of chungkukjang fermented using Bacillus subtilis DJI (DJI CJ) in rats fed high cholesterol diet. Sprague-Dawley male rats weighing 185-195 g were divided into 6 groups: normal group (N), high cholesterol group (C), high cholesterol and DJI CJ with no salt group (C-CJN), high cholesterol and DJI CJ added with solar salt group (C-CJS), high cholesterol and DJI CJ added with refined salt group (C-CJR), and high cholesterol and commercial CJ group (C-CCJ). The body weight gain and food intake in all four CJ groups were lower than C group. The serum activities of AST and ALT that were elevated by high cholesterol diet were significantly decreased by CJ supplemented. The hepatic activities of catalase and SOD in C group were increased to 20.59% and 18.72%, respectively, compared with N group, but those of C-CJN, C-CJS, C-CJR, and C-CCJ groups were similar to those of N group. Liver TBARS contents were significantly decreased in all CJ groups, compared with C group. The contents of brain lipofuscin in C-CJN, C-CJS, C-CJR, and C-CCJ groups were remarkably inhibited about 20.86%, 22.06%, 14.73%, and 12.88%, respectively, compared with C group. There were no significant differences among DJI CJ groups in antioxidative effects. According to this study, DJI chungkukjang or commercial chungkukjang seems to protect tissues from oxidative stress by stimulating antioxidative systems in rats fed a high cholesterol diet.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.8
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• pp.1086-1093
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• 2012

The hypoglycemic and hypolipidemic effects of autoclaved soy flour and DJI chungkukjang powder fermented using Bacillus subtilis DJI were investigated in type 2 diabetic animal models. After a 2-week adaptation period, the diabetic animal model db/db mice were divided into the diabetic control group (D-C group), a diabetic group fed with soybean (D-S group), and a diabetic group fed with DJI chungkukjang (D-CJ group). The body weight gain, food intake, water intake, liver, and adipose tissue weights were not significantly different between the experimental groups. The supplementation of DJI chungkukjang or autoclaved soy flour diet induced a marked reduction of fasting blood glucose, blood glycosylated hemoglobin levels, and glucose levels in the oral glucose tolerance test and AUC for glucose compared with the diabetic control group. However, DJI chungkukjang showed a much stronger antidiabetic effect than unfermented autoclaved soy flour. Serum insulin levels were the same among the groups. The supplementation of DJI chungkukjang or autoclaved soy flour diet also significantly lowered the serum triglyceride, total cholesterol, and LDL-cholesterol levels compared with the control diabetic group, while it elevated the HDL-cholesterol level in the serum. This data suggests that the dietary supplementation of autoclaved soy flour or DJI chungkukjang may be useful in the control of blood glucose in animals with type 2 diabetes.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.333-334
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• 2018

This is a study on controlling a drone (DJI Mavic Air) with simple hand gesture using Leap Motion controller. Four component involve are MacBook, Leap Motion controller, Android device, and DJI Mavic Air. All of this component are connected through USB, Bluetooth, and Wi-Fi technology. The studies main purpose are to show that by controlling a drone through Leap Motion, drone amateur user can easily learn how to control a drone, and because of longer drone control range can be archived things such as search and rescue mission will be possible.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.4
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• pp.609-619
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• 2023

Recently, crimes using drones, one of the IoT industries have been continuously reported. In particular, drones are characterized by easy access and free movement, so they are used for various crimes such as transporting explosives, transporting drugs, and illegal recording. In order to analyze and investigate these criminal acts, drone forensic research is highly emphasized. Media data, PII, and flight records are digital forensic artifacts that can be acquired from drones, in particluar flight records are important artifacts since they can be used to trace drone activities. Therefore, in this paper, the characteristics of the deleted flight record files of DJI drones are presented and verified using the Phantom3, Phantom4 andMini2 models, two drones with differences in characteristics. Additionally, the recovery level is analyzed using the flight record file characteristics, and lastly, drones with the capacity to recover flight records for each drone model and drone models without it are classified.

• The Optical Journal
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• s.158
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• pp.40-47
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• 2015

드론은 군사용으로 제일 먼저 개발되어 시장을 형성했지만, 오픈소스 드론의 제작이 많아지면서 소비자 시장도 급속도로 확대되고 있다. 최근 중국의 DJI는 기업가치 100억 달러 이상을 넘볼 정도로 급성장을 하였고, 드론용 소프트웨어나 플랫폼을 확보한 스타트업 기업들에 대한 투자도 활발하게 이루어지고 있다. 구글이나 페이스북, 아마존 등은 자사의 서비스 강화를 위한 목적으로 드론 기술을 적극적으로 활용하고 있으며, 드론의 시장 확대에 따른 드론 시장 생태계도 크게 확장되고 있다. 최근 드론에 대한 관심이 뜨겁다. 특히 중국의 DJI는 모형 헬리콥터의 비행조종 시스템을 만들다가 전격적으로 소비자 드론 시장에 뛰어들었는데, 2014년 약 5억 달러 정도의 매출을 올렸다고 한다. 이는 2013년과 비교할 때 4배가 증가한 것이며, 2015년에는 또 다시 2배 이상 성장을 할 것으로 보여 올해에는 소비자 드론을 만드는 기업중에서 세계 최초로 10억 달러 매출을 달성할 것으로 예측된다. 당연히 기업가치도 크게 상승해서, 실리콘밸리에서는 DJI의 기업 가치를 100억 달러 이상으로 보고 있다.

• Food Science and Preservation
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• v.17 no.5
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• pp.688-697
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• 2010

We investigated the cholesterol-lowering and body-weight loss effects of Cheonggukjang fermented using Bacillus subtilis DJI in rats fed a high-fat/high-cholesterol diet for 4 weeks. Weight-matched male Sprague-Dawley rats were assigned to one of four groups: a normal diet group (N), a high-fat/high-cholesterol diet group (HFC), a high-fat/high-cholesterol diet with DJI Cheonggukjang group (HFC-SCK), and a high-fat/high-cholesterol with commercial Cheonggukjang group (HFC-CCK). All of body weight and liver and adipose tissue weights increased in animals fed a high-fat/high-cholesterol diet, but decreased significantly in rats fed Cheonggukjang powder, compared with the HFC group. Food intake was lower in the HFC group than in the N group, and that of the HFC-CCK group was the lowest among the four groups. Serum total cholesterol levels were significantly lower in the Cheonggukjang-powder fed groups than the other groups. Serum phospholipid and HDL-cholesterol concentrations were significantly decreased in HFC animals and were markedly increased upon feeding of a Cheonggukjang-containing-diet. Levels of serum LDL-cholesterol, the atherogenic index, and cardiac risk factor assessment indications tended to be decreased in Cheonggukjang powder-fed groups, compared with the HFC group. The total cholesterol level in liver tissue was increased by feeding of a high-fat/high-cholesterol diet, and was significantly reduced when Cheonggukjang powder was present in the diet. The levels of total lipids and triglycerides in adipose tissues were lower in the HFC-SCK group than in the HFC group, whereas no significant differences were evidence when the HFC and the HFC-CCK groups were compared. Fecal weight, moisture level, and total lipid content increased in animals fed Cheonggukjang powder. The activities of HR-LPL and TE-LPL in adipose tissues were increased in the HFC group compared with the Cheonggukjang powder-fed groups. These results indicate that dietary Cheonggukjang may improve lipid metabolism and prevent obesity and hyperlipidemia.