In this study, to control the heading angle of a ship, which is constantly subjected to various internal and external disturbances during the voyage, an LADRC (linear active disturbance rejection control) design that focuses more on improving the disturbance removal performance was proposed. The speed rate of change of the ship’s heading angle due to the turn of the rudder angle was selected as a significant factor, and the nonlinear model of the ship’s maneuvering equation, including the steering gear, was treated as a total disturbance. It is the similar process with an LADRC design for the first-order transfer function model. At this time, the gains of the controller included in LADRC and the gains of the extended state observer were tuned to RCGAs (real-coded genetic algorithms) to minimize the integral time-weighted absolute error as an evaluation function. The simulation was performed by applying the proposed GA-LADRC controller to the heading angle control of the Mariner class vessel. In particular, it was confirmed that the proposed controller satisfactorily maintains and follows the set course even when the disturbances such as nonlinearity, modelling error, uncertainty and noise of the measurement sensor are considered.
A novel L. harbinensis VF was isolated from fermented vinegar and identified through biochemical characteristics and 16S rRNA sequencing analysis. Characteristics of probiotics were studied for acid and bile salt tolerances, hemolytic activity, antibiotic resistance, antimicrobial activity, cell surface hydrophobicity, and aggregation. The survival rates of the isolate were maintained at 68.9% and 95.6% after 3 h incubation at pH 2.0 and 2.5 and were over 74% at bile salt concentrations of 0.3% and 0.5%. The hemolytic activity was confirmed to be -hemolysis. The isolate showed broad antibiotics-resistance in over 12 antibiotics except for trimethoprim/sulfamethoxazole, compared to L. plantarum (KCTC 3108), used as control, and previously reported L. harbinensis. Antimicrobial activity was confirmed against pathogens, B. cereus, E. coli O157:H7, L. monocytogenes, and S. typhimurium, except S. aureus, and it was attributed to produced organic acids (low pH). The hydrophobicity for xylene and chloroform were 16.7% and 20.4%, respectively, lower than those of L. plantarum (41.2% & 49.9%). The auto-aggregation and coaggregation with pathogens were 83.8% and 49.2-87.6% at 24 h incubation, respectively, higher than those of L. plantarum. From this study, L. harbinensis VF is likely to be used as a probiotic strain and is a strong candidate for commercial application.
This study measured the biochemical properties, antioxidants, free sugars, organic acids, trigonelin, chlorogenic acids, and caffeine content of coffee prepared using different extraction methods by adding dried apple powder to develop high-quality functional drinks. Espresso had the highest soluble solids content and brownness at 9.17±0.88oBrix and 1.85±0.57. Its organic acid content was higher in the sample groups than in the control group, whereas the espresso group was highest in citric acid at 2184.11±0.01 mg/mL, malic acid at 2181.35±0.03 mg/mL, fumal acid at 40.42± 0.01 mg/mL, lactic acid at 32.04±0.02 mg/mL, and formic acid at 49890 mg/mL. Additionally, it had the highest sucrose, glucose, fructose, and sorbitol contents (p<0.05). In the trigonelin content, the sample groups showed a higher content than the control group, with the order being espresso > mokapot > water drip > frenchpress > sippon > hand drip (p<0.05). In the content of chlorogenic acid and caffeine, the sample groups showed higher content than the control group, with the order of espresso > mokapot > water drip > siphon > frenchpress > hand drip (p<0.05). As a result, espresso was found to be suitable for developing coffee drinks in manufactured coffee with different extraction methods.
This study investigated the hazard factors based on imported food non-compliance and global food hazard information for the last 4 years to suggest imported food safety management. Food safety management on utensils or packaging containers is appropriately managed for the compounds derived from them. Food safety management on health-functional foods, processed foods, and agricultural products is concentrated on ingredient contents, food additives, and pesticide residuals. Additional hazards are illegal compounds, mycotoxins & pesticide residuals, hygieneindicator microorganisms and food-borne pathogens in health-functional foods, processed foods, and agricultural products, respectively. The continuous increase in hazards related to safety and hygiene in global food hazard information needs additional attention. To reduce the hazard factors, this study proposes that imported food be limited to products certified by HACCP or an equivalent food safety management system because registering foreign food facilities for processed and health-functional foods is mandatory. Additionally, the customs clearance inspections should focus on the hazard factors derived from the global food hazard information system. This study suggests a global food hazard information system that could derive frequently issued hazard factors at a given period and newly issued hazard factors in aspects, such as food items, subcategories, and exporting countries.
The intermediate shaft of sliding type is assembled with coated shaft joint and tube joint. Since the intermediate shaft plays a role of absorbing displacement change due to vibration, the intermediate shaft must have a sliding force value in an appropriate range. In this study, an intermediate shaft assembly system for post-processing of defective intermediate shafts was developed. The intermediate shaft assembly system consists of a wear count prediction model and an automatic wear system. A wear count prediction model was created with the initial assembly sliding force, quality, and set values. As a result of applying the intermediate shaft assembly device, the sliding force of the intermediate shaft was induced within the set value range. And it was prevented from the intermediate shaft defect and eliminated manual work.
통합항해시스템(INS)은 기존 항해 장비들을 통합하여 부가가치를 제공하는 장치로써 항해 업무 수행을 위한 정보와 기능을 다기능표시장치에(MFD)에 통합하는 것으로 정의된다. IMO 성능 기준은 각 업무에 대한 최소 요구사항을 명시하고 있지만, 장비 및 기 능의 목록은 정의하지 않아 제조사마다 INS의 구성이 상이하고 사용자 관점에 기반 한 지침 또한 부족한 실정이다. 본 연구는 선박 운 용상황 및 수행 업무에 따라 사용자가 요구하는 정보를 분석하고, 이를 INS의 MFD에 효과적으로 구조화하여 INS의 사용성을 높이기 위해 수행되었다. INS 관련 국제 기준 및 제조사의 구성 장비 목록을 분석하여 필수 항해 정보들을 선별하고 MFD 사용 경험이 있는 선박 운항자를 대상으로 카드 소팅 테스트를 실시하여 각 INS 업무에 요구되는 정보들을 분류하도록 하였다. 연구의 결과는 제조사들 이 제품 설계 시 사용자 경험을 반영한 정보 구성에 기본적인 가이드로 활용될 수 있을 것이다.
Zinc-ion Batteries (ZIBs) are currently considered to be effective energy storage devices for wearable electronics because of their low cost and high safety. Indeed, ZIBs show high power density and safety compared with conventional lithium ion batteries (LIBs) and exhibit high energy density in comparison with supercapacitors (SCs). However, in spite of their advantages, further current collector development is needed to enhance the electrochemical performance of ZIBs. To design the optimized current collector for high performance ZIBs, a high quality graphene film is suggested here, with improved electrical conductivity by controlling the defects in the graphene film. The graphene film showed improved electrical conductivity and good electron transfer between the current collector and active material, which led to a high specific capacity of 346.3 mAh g-1 at a current density of 100 mA g-1, a high-rate performance with 116.3 mAh g-1 at a current density of 2,000 mA g-1, and good cycling stability (68.0 % after 100 cycles at a current density of 1,000 mA g-1). The improved electrochemical performance is firmly because of the defects-controlled graphene film, leading to improved electrical conductivity and thus more efficient electron transfer between the current collector and active material.