• Title/Summary/Keyword: High-Performance Storage

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Cortex M3 Based Lightweight Security Protocol for Authentication and Encrypt Communication between Smart Meters and Data Concentrate Unit (스마트미터와 데이터 집중 장치간 인증 및 암호화 통신을 위한 Cortex M3 기반 경량 보안 프로토콜)

  • Shin, Dong-Myung;Ko, Sang-Jun
    • Journal of Software Assessment and Valuation
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    • v.15 no.2
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    • pp.111-119
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    • 2019
  • The existing smart grid device authentication system is concentrated on DCU, meter reading FEP and MDMS, and the authentication system for smart meters is not established. Although some cryptographic chips have been developed at present, it is difficult to complete the PKI authentication scheme because it is at the low level of simple encryption. Unlike existing power grids, smart grids are based on open two-way communication, increasing the risk of accidents as information security vulnerabilities increase. However, PKI is difficult to apply to smart meters, and there is a possibility of accidents such as system shutdown by sending manipulated packets and sending false information to the operating system. Issuing an existing PKI certificate to smart meters with high hardware constraints makes authentication and certificate renewal difficult, so an ultra-lightweight password authentication protocol that can operate even on the poor performance of smart meters (such as non-IP networks, processors, memory, and storage space) was designed and implemented. As a result of the experiment, lightweight cryptographic authentication protocol was able to be executed quickly in the Cortex-M3 environment, and it is expected that it will help to prepare a more secure authentication system in the smart grid industry.

Secondary Battery Electrode Material for Next Generation Mobility Power Storage (차세대 모빌리티 전력 저장 이차전지 핵심소재)

  • Yu-Jin Song;Seo-Hyun Kim;Se-Jin Kim;Jae Hoon Kim
    • Clean Technology
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    • v.30 no.3
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    • pp.159-174
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    • 2024
  • The rapid increase in energy consumption based on fossil fuels is accelerating global warming. In particular, the road transportation sector has high carbon dioxide emissions, so transitioning towards electric vehicles is recommended. Thus, the importance of secondary batteries is increasing. Secondary batteries are reversible batteries that use energy and can be reused through a charging and discharging process. Currently, lithium-ion batteries are widely used. Secondary batteries place importance on six major factors: energy, output, lifespan, environmental friendliness, cost, and stability. Research is actively being conducted to satisfy all six factors by understanding the material characteristics of each component of the battery. As it is difficult to move away from lithium as a cathode material, researchers are investigating higher performance materials that mix materials such as cobalt, nickel, manganese, and aluminum with lithium and use graphite, silicon, and lithium metal to increase capacity. In the case of electrolytes, liquid electrolytes are still mainly used. However, solid electrolytes are being studied due to their stability, but additional research must be conducted to satisfy the energy and output factors. This review paper aims to provide an understanding of secondary batteries through an overview of secondary batteries, the materials and characteristics of their components, their technological trends, and their associated companies.

The Analysis and Migration of Bisphenol A Related Compounds from Metal Food Cans (식품용 금속 캔으로부터 비스페놀 A 관련 물질들의 분석 및 이행 연구)

  • Park, Se-Jong;Park, So-Ra;Choi, Jae Chun;Kim, MeeKyung
    • Journal of Food Hygiene and Safety
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    • v.32 no.4
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    • pp.329-335
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    • 2017
  • Analysis method was presented for the simultaneous determination of nine bisphenol A related compounds such as bisphenol A (BPA), phenol, p-tert-butylphenol, bisphenol A diglycidyl ether (BADGE), $BADGE{\cdot}2H_2O$, $BADGE{\cdot}2HCl$, bisphenol F diglycidyl ether (BFDGE), $BFDGE{\cdot}2H_2O$ and $BFDGE{\cdot}2HCl$ migrated from inner coatings of metal food cans by high performance liquid chromatography (HPLC) with fluorescence detection. The method was validated by examining the linearity of calibration curve, the limit of detection (LOD), the limit of quantification (LOQ), recovery and uncertainty. The migration tests of nine BPA related compounds were carried out with four food simulants; deionized water (DW), 4% acetic acid, 50% ethanol and n-heptane. There was not any compound detected in DW, 4% acetic acid and 50% ethanol at $60^{\circ}C$ for 30 min and n-heptane at $25^{\circ}C$ for 60 min. BPA and phenol were migrated into 4% acetic acid and 50% ethanol at $95^{\circ}C$ for 30 min. The concentrations were ranged from 0 to $10.77{\mu}g/L$ of BPA and from 0 to $2.35{\mu}g/L$ of phenol. Canned foodstuffs mostly have long-term shelf life. We investigated migration of nine BPA related compounds according to the variation in storage periods (0~90 days) and temperatures (4, 25 and $60^{\circ}C$). All compounds were not founded during 90 days at $4^{\circ}C$ and $25^{\circ}C$, respectively. However BPA and $BADGE{\cdot}2H_2O$ were founded in DW and 4% acetic acid at $60^{\circ}C$. The migration levels of BPA and $BADGE{\cdot}2H_2O$ were close to the value of LOQ, respectively and did not change significantly as storage period. It was founded from results that the migration of BPA related compounds from metal food cans was controlled to a safe level.

Analysis of the Effect of Objective Functions on Hydrologic Model Calibration and Simulation (목적함수에 따른 매개변수 추정 및 수문모형 정확도 비교·분석)

  • Lee, Gi Ha;Yeon, Min Ho;Kim, Young Hun;Jung, Sung Ho
    • Journal of Korean Society of Disaster and Security
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    • v.15 no.1
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    • pp.1-12
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    • 2022
  • An automatic optimization technique is used to estimate the optimal parameters of the hydrologic model, and different hydrologic response results can be provided depending on objective functions. In this study, the parameters of the event-based rainfall-runoff model were estimated using various objective functions, the reproducibility of the hydrograph according to the objective functions was evaluated, and appropriate objective functions were proposed. As the rainfall-runoff model, the storage function model(SFM), which is a lumped hydrologic model used for runoff simulation in the current Korean flood forecasting system, was selected. In order to evaluate the reproducibility of the hydrograph for each objective function, 9 rainfall events were selected for the Cheoncheon basin, which is the upstream basin of Yongdam Dam, and widely-used 7 objective functions were selected for parameter estimation of the SFM for each rainfall event. Then, the reproducibility of the simulated hydrograph using the optimal parameter sets based on the different objective functions was analyzed. As a result, RMSE, NSE, and RSR, which include the error square term in the objective function, showed the highest accuracy for all rainfall events except for Event 7. In addition, in the case of PBIAS and VE, which include an error term compared to the observed flow, it also showed relatively stable reproducibility of the hydrograph. However, in the case of MIA, which adjusts parameters sensitive to high flow and low flow simultaneously, the hydrograph reproducibility performance was found to be very low.

Effect of Dietary Probiotics Supplementation Contained with Astaxanthin Produced by Phaffia rhodozyma on the Productivity and Meat Quality of Ducks (Astaxanthin을 생성하는 Phaffia rhodozyma를 포함한 미생물제제의 급여가 오리의 성장과 육질에 미치는 영향)

  • Kim K. S.;Lee J. H.;Shin M. S.;Cho M. S.;Kim Y. P.;Cho S. K.;Kang Y. J.
    • Korean Journal of Poultry Science
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    • v.32 no.2
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    • pp.73-80
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    • 2005
  • This study was carried out to investigate the influence of dietary probiotics supplementation contained with astaxanthin synthesizing microorganism 'Phaffia rhodozyma' on the productivity and meat quality of ducks. Growth performance carried out during 45 days for day-old ducks offered in Joowonori incorporated. A total of 150 day-old ducks(cheribery) of mixed sex(M:F=1:1) were allotted into 5 groups. The basal diets were added with low levels of astaxanthin containing probiotics. We investigated mortality, bodyweight, and feed conversion used by growth performance. 45day-old ducks were butchered and carried out nutrients composition analysis, meat quality test, organoleptic examination, fatty acid analysis, cholesterol analysis, storage test, and astaxanthin concentration analysis. Control showed $3.7\%$ mortality and treatments showed $0\%$ mortality. These results showed improvement of immunity, for influence of dietary probiotics supplementation contained with astaxanthin. The control gained 2.68 kg and treatment gained 2.84 kg. The control was 2.15 and treatment was 1.83 for feed conversion. Treatment was increased feed conversion than control as significantly. The results of meat quality test showed that treatment was tender and taste more than control. The results of nutrients composition analysis showed that treatment was produced low fat and high protein meat. Ducks meat of treatments contained higher unsaturated fatty acid and lower cholesterol than control. The case of carotenoids confirmed that astaxanthin and $\beta-carotein$ were accumulated in duck meat.

Simulation of Drying Grain with Solar-Heated Air (태양에너지를 이용한 곡물건조시스템의 시뮬레이션에 관한 연구)

  • 금동혁;김용운
    • Journal of Biosystems Engineering
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    • v.4 no.2
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    • pp.65-83
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    • 1979
  • Low-temperature drying systems have been extensively used for drying cereal grain such as shelled corn and wheat. Since the 1973 energy crisis, many researches have been conducted to apply solar energy as supplemental heat to natural air drying systems. However, little research on rough rice drying has been done in this area, especially very little in Korea. In designing a solar drying system, quality loss, airflow requirements, temperature rise of drying air, fan power and energy requirements should be throughly studied. The factors affecting solar drying systems are airflow rate, initial moisture content, the amount of heat added to drying air, fan operation method and the weather conditions. The major objectives of this study were to analyze the effects of the performance factors and determine design parameters such as airflow requirements, optimum bed depth, optimum temperature rise of drying air, fan operation method and collector size. Three hourly observations based on the 4-year weather data in Chuncheon area were used to simulate rough rice drying. The results can be summarized as follows: 1. The results of the statistical analysis indicated that the experimental and predicted values of the temperature rise of the air passing through the collector agreed well. 2. Equilibrium moisture content was affected a little by airflow rate, but affected mainly by the amount of heat added, to drying air. Equilibrium moisture content ranged from 12.2 to 13.2 percent wet basis for the continuous fan operation, from 10.4 to 11.7 percent wet basis for the intermittent fan operation respectively, in range of 1. 6 to 5. 9 degrees Centigrade average temperature rise of drying air. 3. Average moisture content when top layer was dried to 15 percent wet basis ranged from 13.1 to 13.9 percent wet basis for the continuous fan operation, from 11.9 to 13.4 percent wet basis for the intermittent fan operation respectively, in the range of 1.6 to 5.9 degrees Centigrade average temperature rise of drying air and 18 to 24 percent wet basis initial moisture content. The results indicated that grain was overdried with the intermittent fan operation in any range of temperature rise of drying air. Therefore, the continuous fan operation is usually more effective than the intermittent fan operation considering the overdrying. 4. For the continuous fan operation, the average temperature rise of drying air may be limited to 2.2 to 3. 3 degrees Centigrade considering safe storage moisture level of 13.5 to 14 perceut wet basis. 5. Required drying time decrease ranged from 40 to 50 percent each time the airflow rate was doubled and from 3.9 to 4.3 percent approximately for each one degrees Centigrade in average temperature rise of drying air regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on required drying time. 6. Required drying time increase ranged from 18 to 30 percent approximately for each 2 percent increase in initial moisture content regardless of the fan operation methods, in the range of 18 to 24 percent moisture. 7. The intermittent fan operation showed about 36 to 42 percent decrease in required drying time as compared with the continuous fan operation. 8. Drymatter loss decrease ranged from 34 to 46 percent each time the airflow rate was doubled and from 2 to 3 percent approximately for each one degrees Centigrade in average temperature rise of drying air, regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on drymatter loss. 9. Drymatter loss increase ranged from 50 to 78 percent approximately for each 2 percent increase in initial moisture content, in the range of 18 to 24 percent moisture. 10. The intermittent fan operation: showed about 40 to 50 percent increase in drymatter loss as compared with the continuous fan operation and the increasing rate was higher at high level of initial moisture and average temperature rise. 11. Year-to-year weather conditions had a little effect on required drying time and drymatter loss. 12. The equations for estimating time required to dry top layer to 16 and 1536 wet basis and drymatter loss were derived as functions of the performance factors. by the least square method. 13. Minimum airflow rates based on 0.5 percent drymatter loss were estimated. Minimum airflow rates for the intermittent fan operation were approximately 1.5 to 1.8 times as much as compared with the continuous fan operation, but a few differences among year-to-year. 14. Required fan horsepower and energy for the intermittent fan operation were 3. 7 and 1. 5 times respectively as much as compared with the continuous fan operation. 15. The continuous fan operation may be more effective than the intermittent fan operation considering overdrying, fan horsepower requirements, and energy use. 16. A method for estimating the required collection area of flat-plate solar collector using average temperature rise and airflow rate was presented.

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Simulation of Drying Grain with Solar-Heated Air (태양에너지를 이용한 곡물건조시스템의 시뮬레이션에 관한 연구)

  • Keum, Dong-Hyuk
    • Journal of Biosystems Engineering
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    • v.4 no.2
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    • pp.64-64
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    • 1979
  • Low-temperature drying systems have been extensively used for drying cereal grain such as shelled corn and wheat. Since the 1973 energy crisis, many researches have been conducted to apply solar energy as supplemental heat to natural air drying systems. However, little research on rough rice drying has been done in this area, especially very little in Korea. In designing a solar drying system, quality loss, airflow requirements, temperature rise of drying air, fan power and energy requirements should be throughly studied. The factors affecting solar drying systems are airflow rate, initial moisture content, the amount of heat added to drying air, fan operation method and the weather conditions. The major objectives of this study were to analyze the effects of the performance factors and determine design parameters such as airflow requirements, optimum bed depth, optimum temperature rise of drying air, fan operation method and collector size. Three hourly observations based on the 4-year weather data in Chuncheon area were used to simulate rough rice drying. The results can be summarized as follows: 1. The results of the statistical analysis indicated that the experimental and predicted values of the temperature rise of the air passing through the collector agreed well.2. Equilibrium moisture content was affected a little by airflow rate, but affected mainly by the amount of heat added, to drying air. Equilibrium moisture content ranged from 12.2 to 13.2 percent wet basis for the continuous fan operation, from 10.4 to 11.7 percent wet basis for the intermittent fan operation respectively, in range of 1. 6 to 5. 9 degrees Centigrade average temperature rise of drying air.3. Average moisture content when top layer was dried to 15 percent wet basis ranged from 13.1 to 13.9 percent wet basis for the continuous fan operation, from 11.9 to 13.4 percent wet basis for the intermittent fan operation respectively, in the range of 1.6 to 5.9 degrees Centigrade average temperature rise of drying air and 18 to 24 percent wet basis initial moisture content. The results indicated that grain was overdried with the intermittent fan operation in any range of temperature rise of drying air. Therefore, the continuous fan operation is usually more effective than the intermittent fan operation considering the overdrying.4. For the continuous fan operation, the average temperature rise of drying air may be limited to 2.2 to 3. 3 degrees Centigrade considering safe storage moisture level of 13.5 to 14 perceut wet basis.5. Required drying time decrease ranged from 40 to 50 percent each time the airflow rate was doubled and from 3.9 to 4.3 percent approximately for each one degrees Centigrade in average temperature rise of drying air regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on required drying time.6. Required drying time increase ranged from 18 to 30 percent approximately for each 2 percent increase in initial moisture content regardless of the fan operation methods, in the range of 18 to 24 percent moisture.7. The intermittent fan operation showed about 36 to 42 percent decrease in required drying time as compared with the continuous fan operation.8. Drymatter loss decrease ranged from 34 to 46 percent each time the airflow rate was doubled and from 2 to 3 percent approximately for each one degrees Centigrade in average temperature rise of drying air, regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on drymatter loss. 9. Drymatter loss increase ranged from 50 to 78 percent approximately for each 2 percent increase in initial moisture content, in the range of 18 to 24 percent moisture. 10. The intermittent fan operation: showed about 40 to 50 percent increase in drymatter loss as compared with the continuous fan operation and the increasing rate was higher at high level of initial moisture and average temperature rise.11. Year-to-year weather conditions had a little effect on required drying time and drymatter loss.12. The equations for estimating time required to dry top layer to 16 and 1536 wet basis and drymatter loss were derived as functions of the performance factors. by the least square method.13. Minimum airflow rates based on 0.5 percent drymatter loss were estimated.Minimum airflow rates for the intermittent fan operation were approximately 1.5 to 1.8 times as much as compared with the continuous fan operation, but a few differences among year-to-year.14. Required fan horsepower and energy for the intermittent fan operation were3. 7 and 1. 5 times respectively as much as compared with the continuous fan operation.15. The continuous fan operation may be more effective than the intermittent fan operation considering overdrying, fan horsepower requirements, and energy use.16. A method for estimating the required collection area of flat-plate solar collector using average temperature rise and airflow rate was presented.

Genotype x Environment Interaction and Stability Analysis for Potato Performance and Glycoalkaloid Content in Korea (유전형과 재배환경의 상호작용에 따른 감자 수량성과 글리코알카로이드 함량 변화)

  • Kim, Su Jeong;Sohn, Hwang Bae;Lee, Yu Young;Park, Min Woo;Chang, Dong Chil;Kwon, Oh Keun;Park, Young Eun;Hong, Su Young;Suh, Jong Taek;Nam, Jung Hwan;Jeong, Jin Cheol;Koo, Bon Cheol;Kim, Yul Ho
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.62 no.4
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    • pp.333-345
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    • 2017
  • The potato tuber is known as a rich source of essential nutrients, used throughout the world. Although potato-breeding programs share some priorities, the major objective is to increase the genetic potential for yield through breeding or to eliminate hazards that reduce yield. Glycoalkaloids, which are considered a serious hazard to human health, accumulate naturally in potatoes during growth, harvesting, transportation, and storage. Here, we used the AMMI (additive main effects and multiplicative interaction) and GGE (Genotype main effect and genotype by environment interaction) biplot model, to evaluate tuber yield stability and glycoalkaloid content in six potato cultivars across three locations during 2012/2013. The environment on tuber yield had the greatest effect and accounted for 33.0% of the total sum squares; genotypes accounted for 3.8% and $G{\times}E$ interaction accounted for 11.1% which is the nest highest contribution. Conversely, the genotype on glycoalkaloid had the greatest effect and accounted for 82.4% of the total sum squares), whereas environment and $G{\times}E$ effects on this trait accounted for only 0.4% and 3.7%, respectively. Furthermore, potato genotype 'Superior', which covers most of the cultivated area, exhibited high yield performance with stability. 'Goun', which showed lower glycoalkaloid content, was the most suitable and desirable genotype. Results showed that, while tuber yield was more affected by the environment, glycoalkaloid content was more dependent on genotype. Further, the use of the AMMI and GGE biplot model generated more interactive visuals, facilitated the identification of superior genotypes, and suggested decisions on a variety of recommendations for specific environments.

Assessment of Sanitary Management Practices of School Foodservice Operations in Seoul (서울지역 학교급식 위생관리 실태평가)

  • Kwak, Tong-Kyung;Hong, Wan-Soo;Moon, Hye-Kyung;Ryu, Kyung;Chang, Hye-Ja
    • Journal of Food Hygiene and Safety
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    • v.16 no.3
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    • pp.168-177
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    • 2001
  • Sanitary management practices were assessed to insure the safety of school foodservice, to prevent the outbreak of foodborne illness, and to improve the quality of school foodservice. To accomplish these objectives, a survey was conducted and analyzed on elementary and high school foodservice operations located in Seoul area. A Questionnaire from based on HACCP standards was developed and used for self-reported evaluation of the school foodservice managers on their sanitary management practices. The results were analysed by examining their activities and identifying weaknesses in those activities. The questionnaire was composed of three sectors with all 53 questions; 33 questions for time-temperature management, 5 for personal hygiene and 15 for equipment/facility sanitation. Five-point-scale was used on the questionnaire answers. Among the schools responded,253 (98.4% of the total) were elementary schools and 19 (1.6%) were high schools. Among the three sectors, personal hygiene performance was mostly well conducted by marking average 4.06$\pm$0.57. Equipment/facility sanitation came next by marking average 3.84$\pm$0.53. Time-temperature marked average 3.45$\pm$0.46. “Storage after cooking (2.03$\pm$0.94)”was identified as the least managed activities because the school foodservice operations were not equipped well with hot holding and/or cold holding. “Separate use of sink per usage (3.03$\pm$1.10)” and “proper location of hand washing facility (3.07$\pm$1.13))” were identified as the least practiced activities in equipment/facility sanitation sector. To enhance these practices, proper number of sinks and hand washing facilities should be equipped first within the kitchen area.

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Characterization of SEI layer for Surface Modified Cathode of Lithium Secondary Battery Depending on Electrolyte Additives (전해질 첨가제에 따른 graphite 음극의 SEI분석 및 전기 화학적 특성 고찰)

  • Lee, Sung Jin;Cha, Eun Hee;Lim, Soo A
    • Journal of the Korean Electrochemical Society
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    • v.19 no.3
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    • pp.69-79
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    • 2016
  • Lithium ion battery with high energy density is expanding its application area to electric automobile and electricity storage field beyond existing portable electric devices. Such expansion of an application field is demanding higher characteristic and stable long life characteristic of an anode material, the natural graphite that became commercialized in lithium ion battery. This thesis produced cathode by using natural graphite anode material, analyzed creation of the cathode SEI film created due to initial reaction by using electrolyte additives, VC (vinylene carbonate), VEC (vinyl ethylene carbonate), and FEC (fluoroethylene carbonate), and considered correlation with the accompanying electrochemical transformation. This study compared and analyzed the SEI film variation of natural graphite cathode according to the electrolyte additive with SEI that is formed at the time of initial filling and cathode of $60^{\circ}C$ life characteristic. At the time of initial filling, the profile showed changes due to the SEI formation, and SEI was formed in No-Additive in approximately 0.9 V through EVS, but for VC, VEC, and FEC, the formation reaction was created above 1 V. In $60^{\circ}C$ lifespan characteristic evaluation, the initial efficiency was highest in No-Additive and showed high contents percentage, but when cycle was progressed, the capacity maintenance rate decreased more than VC and FEC as the capacity and efficiency at the time of filling decreased, and VEC showed lowest performance in efficiency and capacity maintenance rate. Changes of SEI could not be verified through SEM, but it was identified that as the cycle of SEI ingredients was progressed through FT-IR, ingredients of Alkyl carbonate ($RCO_2Li$) affiliation of the $2850-2900cm^{-1}$ was maintained more solidly and the resistance increased as cycle was progressed through EIS, and specially, it was identified that the resistance due to No-Additive and SEI of VEC became very significant. Continuous loss of additives was verified through GC-MS, and the loss of additives from partial decomposition and remodeling of SEI formed the non-uniform surface of SEI and is judged to be the increase of resistance.