The research aimed to develop a high-efficiency plate-type heat exchanger for exhaust gas using computational fluid dynamics (CFD) thermal analysis based on the plate shape, and to identify the optimal shape. Following this, a water/air plate heat exchanger was manufactured, and its characteristics were studied experimentally. As the Re number increases on the gas (or air) side, the heat transfer rate increases significantly, whereas an increase in the Re number on the water side leads to a smaller increase in heat transfer. This is attributed to the larger convective heat resistance on the gas side, causing a substantial reduction in gas-side heat resistance as gas velocity increases, resulting in a considerable overall reduction in heat resistance. The fluid flow pressure drop showed similar results between the CFD calculations and experimental outcomes.

Membrane bioreactor (MBR) provides the benefits on high effluent quality and construction cost without the secondary clarification. Despite of these advantages, fouling, which clogs the pore in membrane modules, affects the membrane life span and effluent quality. Studies on the laboratory scale MBR were focused on the control of particulate fouling, organic fouling and inorganic fouling. However, less studies were focused on the control of biofouling and microbial aspect of membrane. In the full scale operation, most MBR produces high effluent quality to meet the national permit of discharge regulation. In this study, the performance and microbial community analysis were investigated in two MBRs. As the results, the performance of organic removal, nitrogen removal, and phosphorus removal was similar both MBRs. Microbial community analysis, however, showed that Azonexus sp. and Propionivibrio sp. contributed to indirect fouling to cause the chemical cleaning in the DX MBR.

γ-aminobutyric acid (GABA) is a natural stress-reducing substance and is actively used as a human health supplement. However, minimal research has been conducted on its use in cattle. This study was conducted to evaluate the effects of GABA on the growth performance, complete blood count, blood metabolites, and carcass characteristics of fattening Hanwoo steers. Twenty-one fattening steers were randomly assigned to one of three treatments: control (basal diet: concentrate feed + rice straw), T1 (basal diet + GABA supplement at 0.8% of feed/head/day), and T2 (basal diet + GABA supplement at 1.6% of feed/head/day). Feed intake and conversion ratio did not differ among the treatments. However, the average daily gain during the early fattening period increased linearly to 0.80 kg, 0.86 kg, and 0.92 kg in the control, T1, and T2 groups (p<0.05). Plasma γ-glutamyl transferase (37.5, 58.2, 42.8 U/ℓ) and creatinine (1.32, 1.34, 1.49 ㎎/㎗) levels in the GABA supplement group were increased compared to those in the control group. The carcass weight (422.7, 427.1, 454.1 kg), rib eye area (86.67, 92.57, 91.14 cm2), and marbling score (3.67, 4.29, 4.14) were numerically higher in the GABA supplement group than in the control group. Thus, GABA supplementation positively affected the average daily gain and carcass characteristics of Hanwoo steers. However, the effect of the GABA supplement level of GABA was small, and further research using rumen-protected coating technology on GABA is necessary.

Recently, the occurrence frequency of earthquake has increased in Korea, and the interests for seismic reinforcement of existing school buildings have been raised. To this end, the seismic performance evaluations for school buildings that did not accomplish the seismic design are required. In particular, this study checks the eigenvalue analysis, pushover curves, maximum base shears, performance points and story drift ratios, and then analyzes the seismic performance characteristics according to bracing configuration of steel frame system reinforcement. Also, this study presents the practical field application methods through the comparison of analysis results for the seismic performance characteristics.

코로나 이후 시기가 도래하며 세계 각국은 빠른 경제 회복을 목표로 다양한 노력을 강구하고 있다. 이러한 측면에서 고성장기업에 관한 관심 역시 지속해서 높아지고 있는데, 지금까지 이루어진 다양한 고성장기업의 연구를 통해 국가 경제발전이나 고용 창출에 있어 고성장기업의 높은 기여도가 입증되었기 때문이다. 이처럼 기존 고성장기업 관련 연구의 경우 국가 경제 차원, 특히 고용 창출에 있어서 고성장기업의 역할을 강조하고 있다. 하지만, 혁신 관점에서 고성장기업의 역할을 언급하고 있는 연구는 많지 않다. 이에 본 연구에서는 기업 재무 데이터와 과학기술정책연구원의 2021년 한국기업혁신조사(KIS)(서비스업 분야)를 병합한 통합데이터를 구축하고 서비스업 고성장기업의 혁신 활동과 혁신성과에 대해 분석해보았다. 방법론 측면에서는 고성장기업이 갖는 특성으로 인해 발생할 수 있는 선택편의 문제를 해결 하기 위해 성향점수매칭방법론을 활용하였다. 분석 결과를 살펴보면 서비스업 고성장기업은 일반기업 대비 더 다양한 혁신 활동을 통해 더 많은 혁신성과물을 창출하고 있는 것으로 나 타났다. 특히, 상품혁신이나 비즈니스 혁신성과물 창출에 있어서 고성장기업이 긍정적인 역 할을 한다는 것은 기존 경제·사회적 관점에서 강조되어오던 고성장기업의 중요성을 혁신성 장 관점으로 확대하여 해석할 수 있는 결과이다. 다만, 연구·개발 유형이나 협력 R&D에서는 일반기업과 차별점을 찾을 수 없었는데, 이는 협력 연구·개발 강화를 통해 고성장기업이 보 유한 혁신역량이 일반기업자들에게 파급될 필요가 있음을 보여주는 결과이다. 이상의 분석 결과를 바탕으로 본 연구에서는 국가 혁신역량 강화를 위한 고성장기업 육성과 모니터링의 필요성, 고성장기업의 협력 활동 유인 통한 혁신의 파급효과 확대 등의 시사점을 제시하고자 한다.

The change in the performance of the range hood according to the pressure change was investigated through a comparative experiment, and the conclusion is as follows. KS C 9304: In 2020, static pressure was applied at 100 Pa according to the fan standard, and the test was conducted by varying the outlet diameter and power consumption. In the case of Motor power 55W, the air volume value was 184.6 when the outlet diameter was 125mm. As a result of the test, if the power consumption is 52.0W, the diameter of the outlet is 125mm, and the power consumption is 60.8W, and the diameter of the outlet is 100mm, it meets 160 or more and less than 200 (constant pressure 100Pa).

Technology innovation companies are focusing on contributing to business performance by R&D project as a strategic tool. Successful R&D leads to corporate competitiveness enhancement, national industrial development, but there are high uncertainty and risks in R&D. Public and private R&D projects are carried out to achieve various purposes. It was verified how the risk management and benefit management of the R&D project affect the detailed R&D project performance between the Public and private domain. The impact of Project Leadership on R&D performance was also analyzed. Those who have participated in the Public and Private R&D projects at companies or research institutes were surveyed. First, it was found that project risk and benefit management have partially an effect on R&D project performance. Second, Public and private R&D Project Leadership showed partially a interaction effect between project management and project performance.

PURPOSES : The purpose of this study was to quantitatively evaluate the variability of LiDAR performance indicators, such as intensity and Number of Point Cloud(NPC), according to various environmental factors and material characteristics. METHODS : To consider the material characteristics of road safety facilities, various materials (Reference Material(RM), reflective sheet, matte sheet, granite, plastic, and rubber) were used in a darkroom, and the performance indicators of LiDAR were repeatedly measured in terms of changes in the measurement distance, rainfall, and angle of observation. RESULTS : In the case of standard reflective materials, the intensity measurement value decreased as the measurement distance and rainfall increased. The NPC showed a tendency to decrease as the measurement distance increased, regardless of rainfall intensity. For materials with high-intensity values, it was found that rainfall intensity and color had negligible effect on the change in intensity compared with the measurement distance. However, for materials with low-intensity values, it was found that the measurement distance, rainfall intensity, and color all had a significant effect on the change in intensity. CONCLUSIONS : For materials with high-intensity values, it was found that rainfall and color had negligible effect on change in intensity compared with the measurement distance. However, for materials with low-intensity values, the measurement distance, rainfall, and color all had a significant effect on the change in intensity value.

Test of the operating characteristics and energy saving performance of a container cooling system that reduces the operating energy of a refrigeration system using a loop thermosyphon heat exchanger that removes heat by temperature difference between outdoor and indoor was performed. As a result of the experiments, when the loop thermosyphon and the refrigeration system were operated simultaneously, the refrigeration system operated intermittently by reducing the heat load. As the temperature difference between indoor and outdoor increased, the operating time of the refrigeration system decreased and the energy efficiency rate increased. Energy efficiency rate showed a tendency to increase with increasing temperature difference, and the predicted correlation of energy efficiency rate using the performance of the loop thermosyphon heat exchanger and the refrigeration system was relatively consistent with the experimental value.

PURPOSES : The purpose of this study was to investigate the characteristics of concrete pavement behaviors and performance depending on the group-axle types of heavy vehicles, such as single-, tandem-, and tridem-axles. METHODS : The concrete pavement performance indices (such as the rate of fatigue cracking and surface smoothness) according to the different group-axle types of heavy vehicles were predicted using the Korean pavement design program. It was assumed that the load magnitude was the same for each axle, and that the equivalent single-axle traffic volumes were the same for the different group-axle types. The concrete pavement stresses depending on the different group-axle types of heavy vehicles were also analyzed using a finite element analysis program. RESULTS : Based on the design criteria, the concrete pavement performance was the highest under tandem-axle traffic and lowest under single-axle traffic, although the difference in performance was not significant. Based on the structural analysis criteria, the tensile stress of the concrete pavement was the largest under the single-axle load and smallest under the tridem-axle load when the load magnitude of each axle was the same. CONCLUSIONS : Based on the results obtained from considering both the design and analysis criteria, it was concluded that the groupaxle types (such as the tandem- and tridem-axle configurations of heavy vehicles) would not increase the stress or decrease the performance of concrete pavements relative to the single-axle configuration.

본 연구는 한우 암송아지 비육프로그램 개발을 위하여 약 8개월령 30두(평균 체중 233kg)에게 전 시험기간동안 한우 거세우 육성용 사료(CP 13.65%, TDN 72.7% 건물기 준)를 자유채식 또는, 제한급여(체중의 1.5%, 1.6%/일)를 시킨 후, 24개월령부터 출하 시(32개월령)까지는 자유 채 식시켰다. 본 시험에서 출하 시 체중은 685-702kg 이었으 며, 전 기간 평균 사료 섭취량(7.78–9.05kg/일)과 증체량 (0.58–0.64kg/일)은 자유채식구가 제한급여구보다 많았다 (p<0.05). 한우 미경산 암소의 배최장근 단면적은 평균 99.9cm2였으며, 도체중은 평균 407kg이었다. 조리 감량은 수분함량이 높고 보수력이 낮을수록 많았다(p<0.05). 등심 중 아미노산 함량은 glutamic acid, aspartic acid, lysine, leucine 순으로 높았으며, 지방산 중에는 oleic acid가 55.9 –58.7% 수준으로 자유채식구가 제한급여구보다 높았다 (p<0.05). 따라서 한우암소 비육 프로그램으로서, 한우 거세우 육 성용 TMR을 전 기간(6-32개월령) 동안 자유 채식시키면, 사료효율, 도체 성적 및 등심의 물리·화학적 특성에 있어 서도 우수한 결과를 나타낼 수 있을 것으로 판단된다.

The prediction of algal bloom is an important field of study in algal bloom management, and chlorophyll-a concentration(Chl-a) is commonly used to represent the status of algal bloom. In, recent years advanced machine learning algorithms are increasingly used for the prediction of algal bloom. In this study, XGBoost(XGB), an ensemble machine learning algorithm, was used to develop a model to predict Chl-a in a reservoir. The daily observation of water quality data and climate data was used for the training and testing of the model. In the first step of the study, the input variables were clustered into two groups(low and high value groups) based on the observed value of water temperature(TEMP), total organic carbon concentration(TOC), total nitrogen concentration(TN) and total phosphorus concentration(TP). For each of the four water quality items, two XGB models were developed using only the data in each clustered group(Model 1). The results were compared to the prediction of an XGB model developed by using the entire data before clustering(Model 2). The model performance was evaluated using three indices including root mean squared error-observation standard deviation ratio(RSR). The model performance was improved using Model 1 for TEMP, TN, TP as the RSR of each model was 0.503, 0.477 and 0.493, respectively, while the RSR of Model 2 was 0.521. On the other hand, Model 2 shows better performance than Model 1 for TOC, where the RSR was 0.532. Explainable artificial intelligence(XAI) is an ongoing field of research in machine learning study. Shapley value analysis, a novel XAI algorithm, was also used for the quantitative interpretation of the XGB model performance developed in this study.

The present study was conducted to examine the effect of soybean silage as a crude protein supplement for corn silage in the diet of Hanwoo steers. The first experiment was conducted to evaluate the effect of replacing corn silage with soybean silage at different levels on rumen fermentation characteristics in vitro. Commercially-purchased corn silage was replaced with 0, 4, 8, or 12% of soybean silage. Half gram of the substrate was added to 50 mL of buffer and rumen fluid from Hanwoo cows, and then incubated at 39°C for 0, 3, 6, 12, 24, and 48 h. At 24 h, the pH of the control (corn silage only) was lower (p<0.05) than that of soybeansupplemented silages, and the pH numerically increased along with increasing proportions of soybean silage. Other rumen parameters, including gas production, ammonia nitrogen, and total volatile fatty acids, were variable. However, they tended to increase with increasing proportions of soybean silage. In the second experiment, 60 Hanwoo steers were allocated to one of three dietary treatments, namely, CON (concentrate with Italian ryegrass), CS (concentrate with corn silage), CS4% (concentrate with corn silage and 4% of soybean silage). Animals were offered experimental diets for 110 days during the growing period and then finished with typified beef diets that were commercially available to evaluate the effect of soybean silage on animal performance and meat quality. With the soybean silage, the weight gain and feed efficiency of the animal were more significant than those of the other treatments during the growing period (p<0.05). However, the dietary treatments had little effect on meat quality except for meat color. In conclusion, corn silage mixed with soybean silage even at a lower level provided a greater ruminal environment and animal performances, particularly with increased carcass weight and feed efficiency during growing period.

The performance characteristics and usefulness of the duct-type gas removal system to which the catalytic combustion method was applied were investigated by experiment. Benzene, toluene, ethylbenzene, and xylene were selected for performance tests on gas detection and removal of the catalytic combustion system. Accelerated experiments were performed to evaluate the gas sensing performance, the adsorption performance of activated carbon, and the basic performance and durability of the catalytic combustion system. The amount of gas adsorption in the adsorption stage was changed according to the type of activated carbon, adsorption temperature and time. The adsorption amount increased with increasing temperature and particle size. BTEX gas removal rate was about 96%, and the performance of the module was maintained for more than 4,000 hours.

본 연구는 보험설계사의 코칭역량과 일터환경특성이 조직성과에 미치는 영향 을 규명하고, 대인관계의 매개효과를 실증적으로 규명하는 데 있다. 본 연구는 보험설계사를 대상으로 총 521부의 구글 설문을 수집하였고, SPSS와 AMOS를 사용하여 분석한 결과는 다음과 같다. 첫째, 보험설계사의 코칭역량과 조직성과 간의 상관관계를 살펴보면, 통계적 으로 유의미한 정적 상관관계가 있으며, 이는 보험설계사의 코칭역량이 높으면 조직성과도 높아짐을 의미한다. 둘째, 보험설계사의 대인관계와 조직성과, 코칭 역량과 대인관계, 일터환경특성과 대인관계 간의 상관관계를 살펴보면, 대부분 의 측정 변인들 간에 통계적으로 유의미한 정적 상관이 있는 것으로 나타났다. 셋째, 보험설계사의 코칭역량과 일터환경특성은 조직성과에 직접적으로 긍정적 인 영향을 미치고, 대인관계의 매개를 통해서도 조직성과에 영향을 미치는 것으 로 예측되어, 대인관계는 코칭역량과 조직성과, 일터환경특성과 조직성과의 관 계를 부분 매개하고 있음을 알 수 있었다. 이 연구를 통해서 보험설계사가 상담 시 사용하는 상담스킬이 코칭에서 사용 되는 코칭역량과 대단히 유사함을 규명하는 연구들이 더 진행되기를 제안한다.