• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.375-380
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• 2003

For some decades eutrophication poses a great problem in water quality management in fresh-waters. To solve this problem, studies based on "bottom-up" hypothesis have been mostly carried out worldwidely unlike biomanipulation. This implies that not only fish but also fish stock playa key role down to other food web components in pelagic ecosystem. It is generally accepted that biomanipulation becomes a potent tool for eutrophication control. For a practical application of this, however, further development and understanding of the food web under the specific lake condition on a whole-lake scale are needed. The question is how can we maintain the positive effects resulted from biomanipulation (fortuitous or planned) for a long period.

• Architectural research
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• v.22 no.3
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• pp.85-95
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• 2020

While there has been a substantial amount of studies on public rental housing of Korea, most have focused on housing policy changes, international comparisons, and current characteristics and future prospects. This article aims to examine the evolving roles of the national and local governments, and the private sector in provision of Korea's public rental housing. The findings suggest that one, although the wave of neoliberalism and financial crisis have prompted the national government to reduce its role and to encourage engagement of other actors by utilizing incentivizing tools, it has continued to assume a central position in formulating and implementing housing supply plans. Two, local governments have played a marginal role throughout the history of public rental housing supply, although they have expanded their participation through redevelopment projects and utilization of existing housings. Three, private sector actors have expanded their role to delivering public benefits of making housing available for a wider range of populace leveraging various incentives that make projects financially more feasible. The study poses a question on how responsibilities and risks can appropriately be allocated among three key actors to achieve housing welfare going forward.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.7
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• pp.3446-3464
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• 2017

Backoff mechanism serves as one of the key technologies in the MAC-layer of wireless mobile networks. The traditional Binary Exponential Backoff (BEB) mechanism in IEEE 802.11 Distributed Coordination Function (DCF) and other existing backoff mechanisms poses several performance issues. For instance, the Contention Window (CW) oscillations occur frequently; a low delay QoS guarantee cannot be provided for real-time transmission, and services with different priorities are not differentiated. For these problems, we present a novel Multi-Priority service differentiated and Adaptive Backoff (MPAB) algorithm over IEEE 802.11 DCF for wireless mobile networks in this paper. In this algorithm, the backoff stage is chosen adaptively according to the channel status and traffic priority, and the forwarding and receding transition probability between the adjacent backoff stages for different priority traffic can be controlled and adjusted for demands at any time. We further employ the 2-dimensional Markov chain model to analyze the algorithm, and derive the analytical expressions of the saturation throughput and average medium access delay. Both the accuracy of the expressions and the algorithm performance are verified through simulations. The results show that the performance of the MPAB algorithm can offer a higher throughput and lower delay than the BEB algorithm.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.851-861
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• 2021

This study aims to explore the specific risks in family small-medium enterprises (SMEs) and explain how they manage these risks to sustain and expand. In Indonesia, family business composes around 95 percent of all businesses and contributes about 80 percent to the country's economy. SMEs contribute approximately 57.8 percent to the nation's gross domestic product. Risk management poses challenges to the family business's survival, as family members do not take actions on risk. The assessment of risk is difficult and family businesses lack the ability to determine risk management priorities, including risk management review processes to evaluate risk, thus leading to family business failures. Applying the case study approach, in-depth semi-structured interviews were conducted in seven family SMEs comprising fifteen informants. Additionally, a focus group discussion consisting of three experts is conducted to reaffirm the findings from the interviews, observations, and field notes. The research identified the specific risks and how the family owners strategize to safeguard against these risks such as cash flow deficiency, operations dysfunction, cultural frailty, disharmony, transgenerational entrepreneurship failure, political uncertainty, and unprofessionalism. Comprehending these risks and their strategic decisions elucidated in this research could enable the family owners and key non-family professionals to work hand-in-hand to thrive over the family business risks together. Further avenues of research regarding family business risk management are also suggested in this study.

• Acta Via Serica
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• v.6 no.1
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• pp.31-54
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• 2021

Radicalisation has become an important issue for the Kyrgyz Republic with an increasing number of individuals leaving the country for conflict zones. The government of the Kyrgyz Republic adopted a number of policies to prevent radicalisation and violent extremism among youth. One of these measures is piloting a new subject, titled, History of Religious Culture, (История религиозной культуры) in public schools. The analysis in this paper aims to explore the experiences of teachers, who have taught the new class. The article also examines any differences in the level of resilience of pupils in schools, piloting and not piloting the new subject, towards radicalisation and violent extremism. Data used in this article comes from a survey with 760 adolescents across public schools in six regions of the country and key informant interviews with teachers who have taught the new class. Qualitative findings showed a positive experience of teachers who reported expanding their pupils' and their own knowledge of various religions. Quantitative findings indicate that the new class, History of Religious Culture, may have had a positive impact on violence-related beliefs in pilot schools that reported views less supportive of violence. The study concludes that the government's response to radicalisation and violent extremism has expanded beyond a security approach by including education. This, however, poses a risk of securitising education.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2708-2715
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• 2021

The Multi-Purpose Overload Robot (CMOR) is a key subsystem of China Fusion Engineering Test Reactor (CFETR) remote handling system. Due to the long cantilever and large loads of the CMOR, it has a large rigid-flexible coupling deformation that results in a poor position accuracy of the end-effector. In this study, based on the Levenberg-Marquardt algorithm, the spatial grid, and the linearized variable load principle, a variable parameter compensation model was designed to identify the parameters of the CMOR's kinematics models under different loads and at different poses so as to improve the trajectory tracking accuracy. Finally, through Adams-MATLAB/Simulink, the trajectory tracking accuracy of the CMOR's rigid-flexible coupling model was analyzed, and the end position error exceeded 0.1 m. After the variable parameter compensation model, the average position error of the end-effector became less than 0.02 m, which provides a reference for CMOR error compensation.

• International Journal of Computer Science & Network Security
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• v.22 no.11
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• pp.57-62
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• 2022

Today, in many countries of the world, the problems of forming and implementing anti-corruption policies are among the most pressing, since the scale of the spread of corruption poses a real threat to national security and democratic development. Without a victory over corruption as a system of social relations, any country will never be able to ensure the safety of its citizens, have a high standard of living, build an efficient economy and a democratic state based on the rule of law, protect its sovereignty, and become competitive among the developed countries of the world community. The main purpose of the article is to analyze the key aspects of the anti-corruption policy of ensuring public order in the state security system. The research methodology includes methods for researching aspects of the anti-corruption policy of ensuring public order in the state security system. Based on the results of the study, the main aspects of the anti-corruption policy of ensuring public order in the state security system are characterized.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.6
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• pp.861-868
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• 2023

One of the key technologies in providing data analysis in the deep learning while maintaining security is fully homomorphic encryption. Due to constraints in operations on fully homomorphically encrypted data, non-arithmetic functions used in deep learning must be approximated by polynomials. Until now, the degrees of approximation polynomials with composite minimax polynomials have been uniformly set across layers, which poses challenges for effective network designs on fully homomorphic encryption. This study theoretically proves that setting different degrees of approximation polynomials constructed by composite minimax polynomial in each layer does not pose any issues in the inference on convolutional neural networks.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.1
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• pp.61-67
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• 2024

A naval mine is an effective weapon system implemented for defending defends ports and seas. A mine is an underwater weapon that poses a great threat to ships sailing over the sea from shallow areas. Most of the influence-type naval mines detect magnetic field signals from ships and determine the final time of fire. Therefore, the level of underwater electro-magnetic signatures of ships is a key requirement for determining the survival of ships in wartime situations where mines are emplaced. The main reason why the high manganese steel is attracting attention for naval ship hulls is its nature as a non-magnetic steel. The non-magnetic hull does not generate electro-magnetic signatures; thus, it has the advantage improving the stealth of the ship. In this paper, I examine whether this material can be applied in the hulls material of naval ships that must be ableto reduce underwater electro-magnetic signatures by considering the non-magnetic characteristics of the first developed high manganese steel in the world.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.5
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• pp.1186-1207
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• 2024

Bearings are one of the main components of mechanical equipment and one of the primary components prone to faults. Therefore, conducting fault diagnosis on bearings is a key issue in mechanical equipment research. Belief rule base (BRB) is essentially an expert system that effectively integrates qualitative and quantitative information, demonstrating excellent performance in fault diagnosis. However, class imbalance often occurs in the diagnosis task, which poses challenges to the diagnosis. Models with interpretability can enhance decision-makers' trust in the output results. However, the randomness in the optimization process can undermine interpretability, thereby reducing the level of trustworthiness in the results. Therefore, a hierarchical BRB model based on extreme gradient boosting (XGBoost) feature selection with interpretability (HFS-IBRB) is proposed in this paper. Utilizing a main BRB alongside multiple sub-BRBs allows for the conversion of a multi-classification challenge into several distinct binary classification tasks, thereby leading to enhanced accuracy. By incorporating interpretability constraints into the model, interpretability is effectively ensured. Finally, the case study of the actual dataset of bearing fault diagnosis demonstrates the ability of the HFS-IBRB model to perform accurate and interpretable diagnosis.