Invasive predators are one of the most damaging species groups to biodiversity. In the Nakdong River, the lake skygazer Chanodichthys erythropterus is a dominant species that is fiercely carnivorous and a concern for commercial fish. Although it is important to understand the ecological characteristics related to the feeding habit, studies on the diets of lake skygazer in Nakdong River have been limited to studies of gut contents. In this study, the trophic position (TP) and feeding habits of C. erythropterus were studied by calculating TPs using samples collected from 13 sites throughout the Nakdong River. Compound-specific isotopic analysis of amino acids provided reliable TPs from the muscle of Lake skygazer C. erythropterus without any isotope baseline. The results were approximately 3 to 3.6 and suggesting a carnivorous but size-dependent prey variation. In particular, the TP variability of C. erythropterus observed in the Nakdong River showed that it had a selective feeding habit compared to carnivorous fish species of relatively similar trophic levels.

Food upcycling has emerged as an effective approach to sustainably utilize the food waste generated within the food supply chain. This review article examines upcycled food with respect to its definition, consumers’ knowledge and perception on it, and the process by which by-products from the food supply chain are utilized for the creation of upcycled food products. The definition of upcycled food varied among manufacturers, research institutions, and the Upcycled Food Association, depending on the specific values and objectives of each sector. This has resulted in the use of different keywords to highlight the distinctive characteristics of their respective interpretations of upcycled food. This review also summarizes the various consumer traits that can influence the awareness and acceptance of upcycled food, encompassing functional, empirical and emotional, symbolic and self-expressive, and economic benefits. Additionally, the review presents strategies to utilize by-products produced in large quantities in Korea, while also addressing the control of hazardous components to ensure biological or chemical safety and the changes in nutritional value that may occur during the utilization of these byproducts.

Despite the consumption of disinfectants have been increased by COVID-19 pandemic, the fate of the chemicals in aquatic food webs are still unclear. In order to understand the trophic transfer of the chemicals, the concentration of disinfectants including six benzalkonium chloride (BACs) and five didecyldimethylammonium chlorides (DDACs) were measured at the Geum (2020), Han (2021), and Yeongsan River (2021), before and after rainfall. The highest concentration of ΣBACs (mainly C12 and C14) and ΣDDACs (mainly C10 and C14) were observed in the Han River, followed by Yeongsan River, Geum River Estuary, and Gapcheon. After rainfalls, both concentration and detection frequency were decreased in all sites. Although the BAC and DDAC seems to be accumulated in organisms, they were bio-diluted rather than magnified in the aquatic food web with the biomagnification factor (BMF) of less than 1, trophic magnification slope (TMS) from - 0.236 to 0.001, and trophic magnification factor (TMF) from 0.85 to 1.01.

The risk of various hazardous substances in aquatic environment comprises not only the concentration of substances in the environmental medium but also their accumulation in fish through complex food web and the health risks to humans through the fish. In Korea, the monitoring of residual toxicant in aquatic ecosystems began in 2016 following the enforcement of the Acts on registration and evaluation for the management of chemicals used in daily life (consumer chemical products), and attention has been paid to potentially hazardous substances attributed to them. Recently, studies have been carried out to investigate the distribution of these hazardous substances in the ecosystem and calculate their emission factors. These include the accumulation and transport of substances, such as detergents, dyes, fragrances, cosmetics, and disinfectants, within trophic levels. This study summarizes the results of recently published research on the inflow and distribution of hazardous substances from consumer chemical products to the aquatic environment and presents the scientific implication. Based on studies on aquatic environment monitoring techniques, this study suggests research directions for monitoring the residual concentration and distribution of harmful chemical substances in aquatic ecosystems. In particular, this study introduces the directions for research on trophic position analysis using compound specific isotope analysis and trophic magnification factors, which are needed to fulfill the contemporary requirements of selecting target fish based on the survey of major fish that inhabit domestic waters and assessment of associated health risk. In addition, this study provides suggestions for future biota monitoring and chemical research in Korea.

PURPOSES : This study aimed to develop data conversion of NGII HD maps to OpenDRIVE format for virtual road implementation for autonomous-driving verification. METHODS : A method of defining the reference line of OpenDRIVE on the centerline of an NGII HD map is proposed. According to the construction characteristics of the NGII HD map, the optimal conversion method through parametric cubic polynomials was used in the form of piecewise and clamped cubic polynomials. RESULTS : The study focused on curved roads that may cause problems when converting HD map data into OpenDRIVE formats. As a result of data conversion, a reference line was defined to precisely follow the alignment of NGII HD maps drawn based on MMS data, and a lively virtual road was reproduced through road lane width and lane expression. CONCLUSIONS : A virtual road in the same environment as a real road, which is one of the important factors in verifying autonomous driving technology through virtual driving simulation, was constructed. The piecewise-polynomial normal was 0.008 m on average, and as a result of calculating the distance between the endpoint coordinates of the road object and the endpoint coordinates of the converted road object on the NGII HD map, the difference between the two points was 0.163 m on average. The clamped cubic polynomials normal was observed to be an average of 0.170 m.

A sediment control dam is an artificial structure built to prolong sedimentation in the main dam by reducing the inflow of suspended solids. These dams can affect changes in dissolved organic matter (DOM) in the water body by changing the river flow regime. The main DOM component for Yeongju Dam sediment control of the Naeseongcheon River was analyzed through 3D excitation-emission matrix (EEM) and parallel factor (PARAFAC) analyses. As a result, four humic-like components (C1~C3, C5), and three proteins, tryptophan-like components (C2, C6~C7) were detected. Among DOM components, humic-like components (autochthonous: C1, allochthonous: C2~C3) were found to be dominant during the sampling period. The total amount of DOM components and the composition ratio of each component did not show a difference for each depth according to the amount of available light (100%, 12%, and 1%). Throughout the study period, the allochthonous organic matter was continuously decomposing and converting into autochthonous organic matter; the DOM indices (fluorescence index, humification index, and freshness index) indicated the dominance of autochthonous organic matter in the river. Considering the relative abundance of cyanobacteria and that the number of bacteria cells and rotifers increased as autochthonous organic matter increased, it was suggested that the algal bloom and consequent activation of the microbial food web was affected by the composition of DOM in the water body. Research on DOM characteristics is important not only for water quality management but also for understanding the cycling of matter through microbial food web activity.

To understand how to efficiently observe the biomass and community of phytoplankton, phytoplankton sampling was carried out from June to October 2019 at the Yeongju dam sediment control reservoir (YJ) and Bohyeonsan dam reservoir (BH1 and BH2). The results derived from microscopic observation, such as the conventional phytoplankton qualitative/quantitative analysis, and from the CHEMTAX method based on the pigments, were compared. The relative contribution of phytoplankton, calculated by the microscopy and CHEMTAX methods, showed a significant difference in all four classes: cryptophyta, chlorophyta, cyanobacteria, and diatoms. In addition, the correlation between the two observation methods was poor. This might be caused by methodological differences in microscopy that do not consider the varying cell sizes among phytoplankton species. In this study, by converting the cells into carbon, the slope between both carbon biomasses based on microscopy and CHEMTAX was improved close to the 1 : 1 line, and the y-intercept was closer to 0 for cryptophyta and diatoms. For cyanobacteria, the slope increased, the y-intercept decreased, and the plot approached 1 : 1 although the correlation coefficients were not improved in all classes. The present study suggests that application of CHEMTAX based on pigment analysis could be a possible approach to efficiently determine the relative carbon proportions of individual classes of phytoplankton community composition.

Diet composition and trophic level of Trachurus japonicus were studied using 417 specimens collected by trawls, set nets and purse seine fisheries from March 2019 to February 2020 in the South Sea of Korea. The size of T. Japonicus ranged from 7.0 to 49.8 cm in total length. T. japonicus were a carnivore that fed mainly on euphausiids and pisces. In eddition, T. japonicus fed on small quantities of cephalopods, crabs etc. T. japonicus showed ontogenetic changes in feeding habits. The proportion of euphausiids decreased inversely proportional to body size whereas the consumption of pisces gradually increased. As body size of T. japonicus increased the mean number of prey per stomach and the mean weight of prey per stomach tended to increase, but the mean number of prey per stomach was not significantly different. As a result of the feeding strategy analysis, T. japonicus were specialized feeders with pisces and euphausiids as their dominant prey. The trophic level ranged between 3.57 ± 0.54 and 3.91 ± 0.65, and increased asymptotically with size of specimens. The average trophic level of the T. japonicus was 3.79 ± 0.61.

In recent years, importance of blockchain systems has been grown after success of bitcoin. Distributed consensus algorithm is used to achieve an agreement, which means the same information is recorded in all nodes participating in blockchain network. Various algorithms were suggested to resolve blockchain trilemma, which refers conflict between decentralization, scalability, security. An algorithm based on Byzantine Agreement among Decentralized Agents (BADA) were designed for the same manner, and it used limited committee that enables an efficient consensus among considerable number of nodes. In addition, election of committee based on Proof-of-Nonce guarantees decentralization and security. In spite of such prominence, application of BADA in actual blockchain system requires further researches about performance and essential features affecting on the performance. However, performance assessment committed in real systems takes a long time and costs a great deal of budget. Based on this motivation, we designed and implemented a simulator for measuring performance of BADA. Specifically, we defined a simulation framework including three components named simulator Command Line Interface, transaction generator, BADA nodes. Furthermore, we carried out response surface analysis for revealing latent relationship between performance measure and design parameters. By using obtained response surface models, we could find an optimal configuration of design parameters for achieving a given desirable performance level.

가속도로부터 변위를 계산 방법 중 상대적으로 사용이 간단한 변위재구성기법이 Lee et al.(2010)과 Hong et al.(2010)에 의해 제안되었다. 목표주파수는 변위재구성기법을 사용할 때 사용자가 결정해야 할 중요한 변수 중 하나로 이것을 결정하기 위해선 주파수영역 분석에 대한 경험이 필요하다. 이 논문은 지진하중을 받는 사장교에 한정된 변위재구성기법의 목표주파수 결정 방법을 제시한다. 사장교가 지진에 의해 가진될 경우 목표주파수는 유효한 모드의 고유주파수 중 가장 낮은 주파수로 결정된다. 여기서 유효한 모드라 함은 가속도의 자유도에 유의미한 영향을 주는 모드형상을 가진 모드를 의미한다. 제안된 목표주파수 결정방법의 타당성을 검증하기 위해 포항지진 발생 당시 측정된 3개 실 교량의 주경간 중앙에서 측정된 가속도와 변위 시간이력을 분석했다. 또한 제안된 방법을 포항지진 발생 당시 측정된 실교량의 주탑 상단 가속도에 적용해 계산된 변위를 분석했다.

Recently, blockchain technology has been recognized as one of the most important issues for the 4th Industrial Revolution which can be represented by Artificial Intelligence and Internet of Things. Cryptocurrency, named Bitcoin, was the first successful implementation of blockchain, and it triggered the emergence of various cryptocurrencies. In addition, blockchain technology has been applied to various applications such as finance, healthcare, manufacturing, logistics as well as public services. Distributed consensus algorithm is an essential component in blockchain, and it enables all nodes belonging to blockchain network to make an agreement, which means all nodes have the same information. For example, Bitcoin uses a consensus algorithm called Proof-of-Work (PoW) that gives possession of block generation based on the computational volume committed by nodes. However, energy consumption for block generation in PoW has drastically increased due to the growth of computational performance to prove the possession of block. Although many other distributed consensus algorithms including Proof-of-Stake are suggested, they have their own advantages and limitations, and new research works should be proposed to overcome these limitations. For doing this, above all things, we need to establish an evaluation method existing distributed consensus algorithms. Based on this motivation, in this work, we suggest and analyze assessment items by classifying them as efficiency and safety perspectives for investigating existing distributed consensus algorithms. Furthermore, we suggest new assessment criteria and their implementation methods, which can be used for a baseline for improving performance of existing distributed consensus algorithms and designing new consensus algorithm in future.

In recent years, imbalanced data is one of the most important and frequent issue for quality control in industrial field. As an example, defect rate has been drastically reduced thanks to highly developed technology and quality management, so that only few defective data can be obtained from production process. Therefore, quality classification should be performed under the condition that one class (defective dataset) is even smaller than the other class (good dataset). However, traditional multi-class classification methods are not appropriate to deal with such an imbalanced dataset, since they classify data from the difference between one class and the others that can hardly be found in imbalanced datasets. Thus, one-class classification that thoroughly learns patterns of target class is more suitable for imbalanced dataset since it only focuses on data in a target class. So far, several one-class classification methods such as one-class support vector machine, neural network and decision tree there have been suggested. One-class support vector machine and neural network can guarantee good classification rate, and decision tree can provide a set of rules that can be clearly interpreted. However, the classifiers obtained from the former two methods consist of complex mathematical functions and cannot be easily understood by users. In case of decision tree, the criterion for rule generation is ambiguous. Therefore, as an alternative, a new one-class classifier using hyper-rectangles was proposed, which performs precise classification compared to other methods and generates rules clearly understood by users as well. In this paper, we suggest an approach for improving the limitations of those previous one-class classification algorithms. Specifically, the suggested approach produces more improved one-class classifier using hyper-rectangles generated by using Gaussian function. The performance of the suggested algorithm is verified by a numerical experiment, which uses several datasets in UCI machine learning repository.

목적: 본 연구에서는 VR(Virtual Reality)기기의 사용이 양안시기능에 미치는 영향에 대해 알아 보고자 하였다. 방법: 본 연구는 양안시기능 이상 및 안질환이 없고, 교정시력이 0.8 이상인 남·여(22.3±1.53 세) 20명을 대상으로 하여 VR기기(Virtual Reality, Samsung:Sm-r325, Korea) 사용 전후 시기능의 변화를 비교 분석하였다. 시기능검사는 자동굴절검안기(Huvitz HRK-8000A Korea)를 통한 굴절이상도, 단안조절근점, 폭주근점, 입체시(Titmus Fly)검사, 근거리 사위도(수정된 토링톤 법)를 측정하였다. 1차 시기능검사 후 30분 동안 VR기기를 사용 하도록 한 후, 검사를 재실시 하여 전과 후의 시기능 변화를 평가하였다. 결과: 굴절이상도는 VR기기 사용 전 등가구면굴절력 S-0.689D에서 사용 후 등가구면굴절력 S-0.754D로 S–0.065D 근시화 변화를 보였고, 조절근점은 VR 사용 전 9.66±2.41cm, VR 사 용 후 11.4±2.57cm로 1.74cm 증가하였으며 폭주근점은 8.56±1.88cm에서 10.03±2.29cm로 1.47cm 증가하였다. 입체시는 79±45.53sec에서 103.5±59.76sec로 24.5sec 차이의 변화를 보였고 근거리 사위도는 4.50±6.48△ 외사위에서 6.40±6.56△ 외사위로 1.90△ 변화량을 보 였다. 결론: 이상의 결과에 따라, VR(Virtual Reality) 기기 사용 후 근시도는 근시방향으로 증가하고, 조절근점과 폭주근점은 거리가 증가하여 조절력과 폭주력이 감소함을 알 수 있었다. 그리고 입체시는 VR 기기 사용 후 감소하고, 근거리 사위도는 외사위 방향으로 증가하였다. 따라서 VR 을 사용한 직 후 굴절검사나 양안시 검사 결과는 변화가 있을 수 있기 때문에 장시간의 VR 사용은 자제하고 적절한 휴식을 취하는 것이 좋을 것으로 사료된다.

This paper provides based on the research of previous researchers of the learning organization, this study selected the factors that would influence the introduction effect of the learning organization operation in the construction companies. The result of this study is that the learning organization operating system has the effect of job performance, job satisfaction, organizational commitment and ultimate The results of this study are as follows.

This paper provides a basic organizational commitment research for the study was conducted academic research, especially acidic improvements in the construction industry for a job commitment on organizational commitment. In this paper, first results are derived for literature to study and improve productivity and derive a major cause of job involvement of construction companies based on it for critical that the rationale organization.