• Journal of the Korean Applied Science and Technology
• /
• v.36 no.2
• /
• pp.645-655
• /
• 2019

In this study, colloidal microgel with viscoelasticity were prepared by using dispersion containing physical crosslinking agents and microgels with various strengths depending on the degree of cross-links.As the chemical crosslinking agent PEGDA400 content increased, hydrogels have various physical properties the swelling ratio decreased from $2.0{\times}10^4%$ to $6.0{\times}10^3%$ and increased viscosity by about 60%. The colloidal microgel was prepared with micro hydrogel grinded to $100{\mu}m$ size and the rheological behavior was confirmed with physical cross linking agent. A colloidal microgel having various viscosities was prepared by controlling starch and alginate based on micro-hydrogel containing 0.75% (w/v) of PEGDA400. In conclusion, these results would be highly useful for applying as a product that can give various physical properties to the colloidal suspensions, cosmetics, paint, and food industry.

• Journal of Life Science
• /
• v.33 no.6
• /
• pp.490-497
• /
• 2023

Pregnant women may need to take medications to treat preexisting diseases or diseases that develop during pregnancy. However, some drugs may be fetotoxic and lead to, for example, teratogenicity and growth retardation. Predicting the fetotoxicity of drugs is thus important for the health of the mother and fetus. The fetotoxicity of many drugs has not been established because various challenges hinder the ability of researchers to determine their fetotoxicity. The need exists for in silico-based fetotoxicity assessment models, as they can modernize the testing paradigm, improve predictability, and reduce the use of animals and the costs of fetotoxicity testing. In this study, we collected data on the fetotoxicity of drugs and constructed fetotoxicity prediction models based on various machine learning algorithms. We optimized the models for more precise predictions by tuning the hyperparameters. We then performed quantitative performance evaluations. The results indicated that the constructed machine learning-based models had high performance (AUROC >0.85, AUPR >0.9) in fetotoxicity prediction. We also analyzed the feature importance of our model's predictions, which could be leveraged to identify the specific features of drugs that are strongly associated with fetotoxicity. The proposed model can be used to prescreen drugs and drug candidates at a lower cost and in less time. It provides a predictive score for fetotoxicity risk, which may be beneficial in the design of studies on fetotoxicity in human pregnancy.

• Tuberculosis and Respiratory Diseases
• /
• v.86 no.3
• /
• pp.203-215
• /
• 2023

Background: Surgical resection is the standard treatment for early-stage lung cancer. Since postoperative lung function is related to mortality, predicted postoperative lung function is used to determine the treatment modality. The aim of this study was to evaluate the predictive performance of linear regression and machine learning models. Methods: We extracted data from the Clinical Data Warehouse and developed three sets: set I, the linear regression model; set II, machine learning models omitting the missing data: and set III, machine learning models imputing the missing data. Six machine learning models, the least absolute shrinkage and selection operator (LASSO), Ridge regression, ElasticNet, Random Forest, eXtreme gradient boosting (XGBoost), and the light gradient boosting machine (LightGBM) were implemented. The forced expiratory volume in 1 second measured 6 months after surgery was defined as the outcome. Five-fold cross-validation was performed for hyperparameter tuning of the machine learning models. The dataset was split into training and test datasets at a 70:30 ratio. Implementation was done after dataset splitting in set III. Predictive performance was evaluated by R² and mean squared error (MSE) in the three sets. Results: A total of 1,487 patients were included in sets I and III and 896 patients were included in set II. In set I, the R² value was 0.27 and in set II, LightGBM was the best model with the highest R² value of 0.5 and the lowest MSE of 154.95. In set III, LightGBM was the best model with the highest R² value of 0.56 and the lowest MSE of 174.07. Conclusion: The LightGBM model showed the best performance in predicting postoperative lung function.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.5B
• /
• pp.547-558
• /
• 2008

With the advent of super cargo ship due to the explosive increase in the amount of cargo shipped via seas, some mega ports are under construction in South Korea, to accommodate the super cargo ship, and some of them already enter their final phase. To sustain the harbor tranquility, mega ports usually comprise huge vertical type breakwaters which are intrinsically vulnerable to the attack of long waves. In this rationale, we present the chamber type breakwater with a circular curtain wall - Eco-breaker 2, to alleviate the reflection of long waves and numerically investigate the hydraulic characteristics of Eco-breaker 2. As a wave driver, we use the Navier-Stokes eq., the most robust wave driver, using SPH (Smoothed Particle Hydrodynamics) and LES (Large Eddy Simulation). For the verification of numerical results, we also carried out hydraulic model test. It is shown that Eco-breaker 2 can effectively alleviate the reflection of long waves with its inherited large organized eddies encompassing the water chamber and some region off the curtain wall of varying size. It is also shown that the scope and strength of large organized eddies strongly depends on the incident wave period, and the reflection coefficient can be lowered to 0.18 by tuning the size of water chamber such that resident time at the chamber is just short of the half period of incident waves. Based on these results, we present the specification of Eco-breaker 2 to boost its use on the development of water environment friendly harbor worldwide.

• The Journal of the Acoustical Society of Korea
• /
• v.27 no.5
• /
• pp.229-238
• /
• 2008

Audio tuning improves not only the sound quality of the car audio but also the quality of the completed car itself. However without the subjective assessment on the users' preferences, it is hard to tune the car audio satisfying them. Even though there are lots of factors to be considered to assess the preferences, only a restricted number of factors should be included in the experiment because the total number of experiments increases rapidly as the number of factors in the experiment increases. A large number of factors make it hard to explore the relationship between the sound quality and the sound characteristics and also makes the panels exhausted. In this paper, 8 sound characteristics, each with 2 levels, are considered for the experiment. An orthogonal design of experiment is suggested to reduce the number of experiments from 256 to 16. The analysis of variance is applied to show that Treble is the most significant characteristic of the reproduced sound of the given pop music. Also Deep Bass, SAD, and the interaction between Treble and SAD are found to be significant. For the given classic music, SAD is the only characteristic which turns out to be significant.

• Informatization Policy
• /
• v.31 no.2
• /
• pp.3-38
• /
• 2024

Hallucination is a significant barrier to the utilization of large-scale language models or multimodal models. In this study, we collected 654 computer science papers with "hallucination" in the abstract from arXiv from December 2022 to January 2024 following the advent of Chat GPT and conducted frequency analysis, knowledge network analysis, and literature review to explore the latest trends in hallucination research. The results showed that research in the fields of "Computation and Language," "Artificial Intelligence," "Computer Vision and Pattern Recognition," and "Machine Learning" were active. We then analyzed the research trends in the four major fields by focusing on the main authors and dividing them into data, hallucination detection, and hallucination mitigation. The main research trends included hallucination mitigation through supervised fine-tuning (SFT) and reinforcement learning with human feedback (RLHF), inference enhancement via "chain of thought" (CoT), and growing interest in hallucination mitigation within the domain of multimodal AI. This study provides insights into the latest developments in hallucination research through a technology-oriented literature review. This study is expected to help subsequent research in both engineering and humanities and social sciences fields by understanding the latest trends in hallucination research.

• Strategy21
• /
• s.33
• /
• pp.5-36
• /
• 2014

This article aims to analyze the diplomatic challenges currently facing China as well as the foreign policy the Xi Jinping administration is adopting to address them. With these purposes in mind, it will look into three areas: first, diplomatic tasks confronting the Xi leadership; second, foreign policy that the Xi administration has implemented since the 18th Party Congress in 2012; and third, the prospects for China's foreign policy under the Xi leadership. As the Xi Jinping administration entered into office, it has encountered two major diplomatic challenges. One is the searching for a new foreign policy, and the other the restructuring of the existing foreign affairs and national security systems. The Xi administration, during its first year in office, has responded actively to tackle these issues. To begin with, it has attempted to make some adjustments on foreign policy while maintaining the Deng Xiaoping line of foreign policy. One of these modifications is placing emphasis on national "core interest," as illustrated by changes in guideline for maritime conflicts, pushing for building maritime power, and proclamation of Air Defense Identification Zone in the East China Sea. Second is the decision on the new guideline for peripheral diplomacy. That is, the administration regarded creating peaceful and stable environments to realize "Chinese Dream" as an important goal of foreign policy, and proposed such new guiding ideology as "familiarity, integrity, benefit, and accommodation." In additoin, the Xi administration restructured the existing foreign affairs and national security systems. Establishing the Central State Security Committee and the Internet Leading Small Group (LSG) are cases in point. As comprehensive organizations for policy coordination that encompass party, government, and military, the two LSGs are in charge of enacting related policies and fine-tuning policy implementation, based upon leadership consisting of chiefs of each relevant organs. Moreover, since Xi himself became the chief of these two newly-found organs, the conditions under which these LSGs could demonstrate unified leadership and adjusting role in its implementation of military, diplomatic, and security policies were developed. The future Chinese diplomacy will be characterized with three main trends. First, peripheral diplomacy will be reinforced. The peripheral diplomacy has become far more important since the Work Conference on Peripheral Diplomacy in October 2013. Second, economic diplomacy will be strengthened with an eye on reducing the "China Threat Theory," which still exists in Asia. Third, the policies to isolate the Philippines and Japan will continue in regard to maritime disputes. All in all, Chinese diplomacy in the Xi Jinping era is likely to feature practical diplomacy which combines both hard and soft approaches to best realize Chinese national interest.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.31 no.1
• /
• pp.84-92
• /
• 1995

The methods by turning circle test and maneuvering indices have been used to study and evaluate the maneuverability of a ship. However recently many studies utilizing the GPS are made on the measurement of the turning circle and in the fishery and hydrographic survey. In this paper, the author carried out the turning circle test using the differential GPS and dumb card together, and compared the data measured by them and analyzed the accuracies of them to obtain the utility basic ones on the measurement of the turning circle by the DGPS. The main results area s follows : 1) To check the accuracies of the GPS, the circling experiments of 50m radius by the DGPS were made on the ground. The accuracies of turning circle measured by the DGPS were found to be very high as the errors of 1.5m. 2) the turning circle by the DGPS could be measured very accurately, by the seed, rudder angle, starboard and port respectively. 3) The turning circle measured by the dumb card was found to be measured accurately as much as the DGPS, when using large rudder angle, the turning circle was large, the turning circle by the dumb car could not be measured accurately on account of large error of bearing of compass. 4) The tactical diameters by the DGPS in case of the rudder angle 35。~5。, were found to be 2.6。15.0 times the Lpp of S.T HAELIM-3 at her slow speed 2.8~16.6 times her Lpp at her half speed, 3.1~17.4 times her Lpp at her full speed. The tactical diameter by the dumb card was found to be 2.4~9.5 times, 2.6~9.6 times, 3.2~12.2 times her Lpp respectively, in the above case and speed.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.11b
• /
• pp.46-48
• /
• 2005

이동 컴퓨팅 환경에서 다수의 이동 클라이언트들에게 데이터를 전달할 때는 클라이언트들의 동시 데이터 접근을 지원하는 브로드캐스트 기법을 사용하면 무선 채널 대역폭의 협소함과 클라이언트 측의 에너지 제약과 같은 단점을 해결할 수 있다. 기존 기법들은 클라이언트의 데이터에 대한 접근빈도(access frequencies)와 클라이언트의 에너지 효율(energy efficiency)을 동시에 고려하지 않았다. 따라서 원하는 데이터가 올 때까지 계속해서 채널을 들어야 함으로 인해 에너지 소비를 많이 하거나, 데이터를 얻을 때까지 추가한 많은 양의 정보에 따른 지연이 발생하는 단점이 있다. 본 논문에서는 클라이언트의 에너지 절약을 위한 tuning time을 최소화하고 실제 데이터를 얻을 때까지 소요되는 access time의 효율을 높이기 위해 데이터의 접근빈도와 에너지 효율을 동시에 고려하는 HIDAF: Hybrid Index considering Data Access Frequencies 기법을 제한한다. 제안하는 기법은 트리기반 기법과 해싱기반 기법을 함께 적용하여 구성한 인덱스를 브로드캐스트 주기에 배치한다. HIDAF 기법은 데이터 접근빈도를 고려한 트리기반 인덱스를 배치함으로써 데이터를 얻기 위한 클라이언트들의 평균 access time을 줄일 수 있고, 이러한 인덱스에 해싱기반 기법을 추가함으로써 클라이언트의 에너지 효율을 최소화하는 새로운 브로드캐스팅 기법이다. HIDAF 기법은 브로드캐스트 추기에 데이터의 접근빈도를 고려한 인덱스를 교차로 추가하여 핫 데이터에 대한 클라이언트들의 access time을 줄임으로써 전체 사용자에 대한 평균 access time을 최소화하는 동시에 클라이언트들의 제한된 에너지 소비를 최소화하는데 목적이 있다. 제안기법에 대한 평가는 수학적 분석을 통해 HIDAF 기법과 기존의 브로드캐스트 기법의 성능을 비교 분석한다.하였으나 사료효율은 증진시켰으며, 후자(사양, 사료)와의 상호작용은 나타나지 않았다. 이상의 결과는 거세비육돈에서 1) androgen과 estrogen은 공히 자발적인 사료섭취와 등지방 침적을 억제하고 IGF-I 분비를 증가시키며, 2) 성선스테로이드호르몬의 이 같은 성장에 미치는 효과의 일부는 IGF-I을 통해 매개될 수도 있을을 시사한다. 약 $70 {\~} 90\%$의 phenoxyethanol이 유상에 존재하였다. 또한, 미생물에 대한 항균력도 phenoxyethanol이 수상에 많이 존재할수록 증가하는 경향을 나타내었다. 따라서, 제형 내 oil tomposition을 변화시킴으로써 phenoxyethanol의 사용량을 줄일 수 있을 뿐만 아니라, 피부 투과를 감소시켜 보다 피부 자극이 적은 저자극 방부시스템 개발이 가능하리라 보여 진다. 첨가하여 제조한 curd yoghurt는 저장성과 관능적인 면에서 우수한 상품적 가치가 인정되는 새로운 기능성 신제품의 개발에 기여할 수 있을 것으로 사료되었다. 여자의 경우 0.8이상이 되어서 심혈관계 질환의 위험 범위에 속하는 수준이었다. 삼두근의 두겹 두께는 남녀 각각 $20.2\pm8.58cm,\;22.2\pm4.40mm$으로 남녀간에 유의한 차이는 없었다. 조사대상자의 식습관 상태는 전체 대상자의 $84.4\%$가 대부분이 하루 세끼 식사를 규칙적으로 하고 있었으며 식사속도는 허겁지겁 빨리 섭취하는 경우가 남자는 $31.0\%$, 여자는 $21.4\%$로 나타났고 이들을 제외한 나머지 사람들은 보통 속도 혹은 충분한 시간을 가지고 식사를 하였다. 평소 식사량은 조금 적게 혹은 적당하게 섭취하는 사람이 대부분이었으며 남자가 여자보다는 배부르게 먹는 경 향이 유의적으로 높았다(p<0.05). 식사는 혼자 하는 경우가 남자

• Journal of Life Science
• /
• v.27 no.4
• /
• pp.423-429
• /
• 2017

Hair color is determined by kind and amount of melanin. Melanocyte mainly synthesizes melanin from L-tyrosine by stimulation of ultra violet. Reactive oxygen species (ROS) play an important role in greying hair. Polygonum multiflorum radix has been reported to inhibit the aging process that black color of hair is turned into grey color. The aim of this study is to investigate the effect of Polygoni multiflorium radix ethanol extract (PMEE) on melanin synthesis related to black hair growth. In anti-oxidant experiment, PMEE decreased DPPH radical and increased reducing power, indicating that PMEE could eliminate ROS involved in greying hair. PMEE decreased cell viability in a dose-dependent manner. Furthermore, the effect of PMEE on the production of melanin was determined by DOPA assay and tyrosinase activity. PMEE increased tyrosinase activity and promoted melanin synthesis. In addition, the expression levels of tyrosinase, tyrosinase related protein-1 (TRP-1), tyrosinase related protein-2 (TRP-2) and microphthalmia-associated transcription factor (MITF), as well as anti-oxidant enzymes such as superoxide dismutase (SOD-3) and catalase were examined using western blot analysis. The expression levels of SOD-3 and catalase were decreased due to the enhanced antioxidant activity of PMEE. In particular, PMEE increased the expression levels of tyrosinase and TRP-2. These results suggest that PMEE could promote melanin synthesis that involved in tuning gray hair into black hair.